Devices, Methods, and Systems for Prosthetic Meniscus Selection, Trialing, and Implantation

ABSTRACT

Methods of selecting and implanting prosthetic devices for use as a replacement meniscus are disclosed. The selection methods include a pre-implantation selection method and a during-implantation selection method. The pre-implantation selection method includes a direct geometrical matching process, a correlation parameters-based matching process, and a finite element-based matching process. The implant identified by the pre-implantation selection method is then confirmed to be a suitable implant in the during-implantation selection method. In some instances, the during-implantation selection method includes monitoring loads and/or pressures applied to the prosthetic device and/or the adjacent anatomy. In some instances, the loads and/or pressures are monitored by a trial prosthetic device comprising one or more sensors. Methods of implanting meniscus prosthetic devices are also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/547,053 filed on Aug. 25, 2009 and is hereby incorporated byreference in its entirety.

BACKGROUND Field

The present disclosure generally relates to medical prosthetic devices,systems, and methods. More specifically, in some instances the presentdisclosure relates to prosthetic devices that replace at least part ofthe functionality of the natural meniscus. Each knee has two menisci, alateral meniscus and a medial meniscus. Each meniscus is acrescent-shaped fibrocartilaginous tissue attached to the tibia at ananterior and a posterior horn. Damage to the meniscus can cause pain andarthritis. Accordingly, it is desirable to replace the damaged naturalmeniscus with a prosthetic device. In some instances the prostheticdevices of the present disclosure are configured to be surgicallyimplanted into a knee joint to replace or augment the natural meniscus.In many instances, it is important that the prosthetic device be of theappropriate size and shape for the intended patient and that theprosthetic device provide the appropriate functionality to the kneejoint. At least in part, the methods of the present disclosure identifysuitable prosthetic devices for use with a particular patient.

While existing devices, systems, and methods have attempted to addressthese issues, they have not been satisfactory in all respects.Accordingly, there is a need for the improved devices, systems, andmethods in accordance with the present disclosure.

SUMMARY

Methods, systems, and devices for selecting, trialing, and/or implantingprosthetic devices for use as a replacement meniscus are disclosed.

In some embodiments, methods for selecting a suitable prosthetic devicefor a particular patient are disclosed. In some instances, the selectionmethods include a pre-implantation selection method and aduring-implantation selection method. In some instances, the implantidentified by the pre-implantation selection method is confirmed to be asuitable implant by the during-implantation selection method.

In some embodiments, prosthetic devices for use as a replacementmeniscus are disclosed. In some instances, the prosthetic devicesinclude sensors for monitoring loads and/or pressures applied to theprosthetic device and/or the adjacent anatomy. In some instances, theprosthetic devices comprise trial meniscus prosthetic devices fortemporary placement within the knee joint.

Additional aspects, features, and embodiments of the present disclosureare described in the following detailed description.

BRIEF DESCRIPTION OF DRAWINGS

Other features and advantages of the present disclosure will becomeapparent in the following detailed description of embodiments of thedisclosure with reference to the accompanying of drawings, of which:

FIG. 1 is a block diagram of an embodiment of a method according to oneaspect of the present disclosure for selecting an appropriate prostheticdevice for use with a patient's knee.

FIG. 2 is a block diagram of an embodiment of a method according to oneaspect of the present disclosure for selecting an appropriate prostheticdevice for use with a patient's knee prior to surgery.

FIG. 3 is a diagrammatic side view of a rendering knee joint where thebone, articular cartilage, and meniscus have been segmented according toone aspect of the present disclosure.

FIG. 4 is a diagrammatic perspective view of a three-dimensionalreconstruction of a natural meniscus according to one aspect of thepresent disclosure.

FIG. 5 is a diagrammatic perspective view of a prosthetic device for usein replacing a damaged natural meniscus according to the presentdisclosure shown in comparison to the dimensions of a healthy naturalmeniscus.

FIG. 6 is a cross-sectional top view of a knee joint based on an MRIand/or CT scan of the knee joint identifying measurements of theanatomical features of the knee joint according to one aspect of thepresent disclosure.

FIG. 7 is a cross-sectional top view of a knee joint based on an MRIand/or CT scan of the knee joint similar to that of FIG. 6, butidentifying measurements of other anatomical features according to oneaspect of the present disclosure.

FIG. 8 is a cross-sectional sagittal view of a knee joint based on anMRI and/or CT scan of the knee joint identifying a medial meniscusheight according to one aspect of the present disclosure.

FIG. 9 is a cross-sectional side view of a knee joint based on an MRIand/or CT scan of the knee joint identifying anterior and posteriormeniscus heights according to one aspect of the present disclosure.

FIG. 10 is a cross-sectional front view of a knee joint based on an MRIand/or CT scan of the knee joint identifying measurements of anatomicalfeatures of the knee joint according to one aspect of the presentdisclosure.

FIG. 11 is a cross-sectional side view of a knee joint based on an MRIand/or CT scan of the knee joint identifying measurements of anatomicalfeatures of the knee joint according to one aspect of the presentdisclosure.

FIG. 12 is a partial cross-sectional top view of a knee joint based onan MRI and/or CT scan of the knee joint identifying measurements ofanatomical features of the knee joint according to one aspect of thepresent disclosure.

FIG. 13 is a partial cross-sectional bottom view of a knee joint basedon an MRI and/or CT scan of the knee joint identifying measurements ofanatomical features of the knee joint according to one aspect of thepresent disclosure.

FIG. 14 is a diagrammatic top view of a meniscus identifyingmeasurements associated with the meniscus according to one aspect of thepresent disclosure.

FIG. 15 is a chart setting forth various correlation parametersaccording to one aspect of the present disclosure.

FIG. 16 is a diagrammatic schematic view of MRI slices according to oneaspect of the present disclosure.

FIG. 17 is a diagrammatic schematic view of MRI slices similar to thatof FIG. 16, but showing an alternative embodiment of the presentdisclosure.

FIG. 18 is a diagrammatic schematic view of MRI slices similar to thatof FIGS. 16 and 17, but showing an alternative embodiment of the presentdisclosure.

FIG. 19 is a diagrammatic perspective view of a three-dimensional finiteelement model of a knee joint according to one aspect of the presentdisclosure.

FIG. 20 is a rendering of a simulated contact pressure map between aprosthetic device and a tibialis plateau according to one aspect of thepresent disclosure.

FIG. 21 is a perspective view of a system for monitoring loads across aknee joint according to one aspect of the present disclosure.

FIG. 22 is a rendering of a contact pressure map of a prosthetic deviceaccording to one aspect of the present disclosure.

FIG. 23 is a rendering of a plurality of contact pressure maps ofvarious prosthetic devices according to one aspect of the presentdisclosure.

FIG. 24 is a block diagram of an embodiment of a method according to oneaspect of the present disclosure for selecting an appropriate prostheticdevice for use with a patient's knee during surgery.

FIG. 25 is a block diagram of a surgical protocol according to oneaspect of the present disclosure.

FIG. 26 is a block diagram of a method for implanting a prostheticdevice into a patient's knee for use in the surgical protocol of FIG. 25according to one aspect of the present disclosure.

FIG. 27 is a block diagram of a method for implanting a prostheticdevice into a patient's knee for use in the surgical protocol of FIG. 25according to another aspect of the present disclosure.

FIG. 28 is a diagrammatic perspective view of a prosthetic deviceaccording to one aspect of the present disclosure.

FIG. 29 is a diagrammatic perspective view of a prosthetic devicesimilar to that of FIG. 28, but showing an alternative embodiment of thepresent disclosure.

FIG. 30 is a diagrammatic perspective view of a prosthetic devicesimilar to that of FIGS. 28 and 29, but showing an alternativeembodiment of the present disclosure.

FIG. 31 is a diagrammatic cross-sectional view of a prosthetic deviceaccording to one aspect of the present disclosure.

FIG. 32 is a diagrammatic cross-sectional view of a prosthetic devicesimilar to that of FIG. 31, but showing an alternative embodiment of thepresent disclosure.

FIG. 33 is a diagrammatic cross-sectional view of a prosthetic devicesimilar to that of FIGS. 31 and 32, but showing an alternativeembodiment of the present disclosure.

FIG. 34 is a diagrammatic schematic view of a prosthetic deviceaccording to one aspect of the present disclosure.

FIG. 35 is a diagrammatic side view of a system according to one aspectof the present disclosure.

FIG. 36 is a diagrammatic side view of a system similar to that of FIG.35, but showing an alternative embodiment of the present disclosure.

FIG. 37 is a screen shot of a user interface of a system for identifyinga suitable prosthetic device for a patient according to one aspect ofthe present disclosure.

FIG. 38 is another screen shot of the user interface of the system foridentifying a suitable prosthetic device for a patient of FIG. 37.

FIG. 39 is another screen shot of the user interface of the system foridentifying a suitable prosthetic device for a patient of FIGS. 37 and38.

FIG. 40 is another screen shot of the user interface of the system foridentifying a suitable prosthetic device for a patient of FIGS. 37, 38,and 39.

FIG. 41 is another screen shot of the user interface of the system foridentifying a suitable prosthetic device for a patient of FIGS. 37, 38,39, and 40.

FIG. 42 is another screen shot of the user interface of the system foridentifying a suitable prosthetic device for a patient of FIGS. 37, 38,39, 40, and 41.

FIG. 43 is another screen shot of the user interface of the system foridentifying a suitable prosthetic device for a patient of FIGS. 37, 38,39, 40, 41, and 42.

FIG. 44 is a bar graph showing a scoring of a library of prostheticdevices according to one aspect of the present disclosure.

FIG. 45 is a bar graph showing a scoring of a library of prostheticdevices similar to that of FIG. 44, but showing an alternativeembodiment of the present disclosure.

FIG. 46 is a bar graph showing a scoring of a library of prostheticdevices similar to that of FIGS. 44 and 45, but showing an alternativeembodiment of the present disclosure.

FIG. 47 is another screen shot of the user interface of the system foridentifying a suitable prosthetic device for a patient of FIGS. 37, 38,39, 40, 41, 42, and 43.

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles of thepresent disclosure, reference will now be made to the embodimentsillustrated in the drawings, and specific language will be used todescribe the illustrated embodiments. It is nevertheless understood thatno limitation of the scope of the disclosure is intended. Any and allalterations or modifications to the described devices, instruments,and/or methods, as well as any further application of the principles ofthe present disclosure that would be apparent to one skilled in the artare encompassed by the present disclosure even if not explicitlydiscussed herein. Further, it is fully contemplated that the features,components, and/or steps described with respect to one embodiment may becombined with the features, components, and/or steps described withrespect to other embodiments of the present disclosure.

In some embodiments, a prosthetic device is selected for a patient froma finite library or catalog of available prosthetic device. In thatregard, the available prosthetic devices are of various sizes, variousmaterials, and/or various shapes. In some instances, a selectionmethodology is applied to identify one or more suitable prostheticdevices and/or a best prosthetic device for a patient based on thepatient's anatomical features. In other instances, a custom prostheticdevice is designed and manufactured specifically for the patient basedon the patient's anatomical features. Specific methods for identifyingthe appropriate prosthetic device(s) for a patient will now bedescribed. It is recognized that the methods described herein may beused individually, combined with one another, and/or combined with othermethods in an effort to identify one or more suitable prosthetic devicesfor the patient.

In most healthy patient knees, the natural meniscus and the surroundingbone structures have substantially matching geometrical contours.Accordingly, in some instances in order to restore the function of theknee joint with a prosthetic meniscus, the prosthetic device isconfigured to substantially match the geometrical contours of thesurrounding bone structures of the knee joint after implantation and/ormimic the function of a natural healthy meniscus. Thus, in someembodiments the geometrical attributes of the patient's knee joints andthe prosthetic device are taken into consideration. In that regard, insome instances the geometrical attributes of both the patient's healthyknee and the patient's damaged knee are considered, including the bonestructures, the articular cartilage, and/or the menisci.

Referring now to FIG. 1, shown therein is a method 200 for identifyingat least one suitable prosthetic device for a patient. The method 200includes a pre-implantation matching process at step 202 and aduring-implantation matching process at step 204. The pre-implantationand during-implantation matching procedures 202 and 204 described hereinare utilized for both medial and lateral meniscus replacements in boththe left and right knees. The method 200 begins at step 202 with thepre-implantation matching process. The pre-implantation matching processof step 202 is comprised of one or more matching methods.

Referring to FIG. 2, in the present embodiment the pre-implantationmatching process 202 comprises three different matching methods: adirect geometrical matching method 206, a correlation parameters-basedmatching method 208, and a finite element-based matching method 210.Each of these three matching processes 206, 208, and 210 is described ingreater detail below. While these processes 206, 208, and 210 aredescribed as being used together, in some instances only one or two ofthe three methods are utilized in the pre-implantation matching process202. In other instances, the processes 206, 208, and 210 are utilized incombination with additional and/or alternative matching processes.

The direct geometrical matching process 206 begins at step 212 where CT,MRI, and/or medical imaging scans of the healthy knee of a candidatepatient are obtained. In some instances, the CT, MRI, and/or medicalimaging scans of the healthy knee are utilized to obtain measurements ofthe patient's knee structures in an effort to identify the appropriateprosthetic device for the damaged knee. While the present disclosurespecifically refers to CT and MRI scans, it is fully contemplated thatother medical imaging methods may be utilized. Accordingly, it is fullycontemplated that alternative medical imaging devices and methods nowknown or in the future developed may be utilized with any and all of themethods described herein.

At step 214, the healthy knee joint is segmented into its variouscomponents. In some embodiments, image-processing algorithms areutilized to segment the knee joint. In some embodiments, one or more ofthe bone surfaces, the articular cartilage, and the meniscus of the kneejoint are segmented. For example, referring to FIG. 3, shown therein isa diagrammatic side view of a patient's right knee joint 250 where thebone surfaces 252 and articular cartilage 254 of the femur 256 and thetibia 258 have been segmented. Further, the medial meniscus 260extending between the articular cartilage 254 has been segmented. Insome instances, the bone surfaces, the articular cartilage, and themeniscus are segmented in separate steps. In other instances, thesegmentation of the bone surfaces, the articular cartilage, and themeniscus are performed approximately simultaneously. In someembodiments, the internal knee joint cavity is characterized based onthe surfaces of the articular cartilage. In some instances, the healthymeniscus is defined at least partially based on the knee joint cavitydefined by the articular cartilage.

Referring again to FIG. 2, in some embodiments at step 214 or asubsequent step of the direct geometrical matching process 206, avirtual solid model 262 of the healthy meniscus 260 is builtgraphically, as shown in FIG. 4. In some embodiments, the virtual solidmodel 262 is created in a stereolithography (“STL”) format. In otherinstances, other known modeling formats are utilized. The virtual model262 is used in some instances to compare the healthy meniscus 260 to theavailable prosthetic devices.

In some instances both knees of a candidate patient are damaged or atleast not suitable for use as a model healthy meniscus. In suchinstances, a model healthy meniscus for the patient is selected from alibrary of model healthy menisci or formulated specifically for thepatient based on the geometrical measurements of the patient's kneecomponents. In that regard, in some embodiments a library of modelhealthy menisci are maintained in a database. The healthy menisci arebased on one or more cadaver studies in some instances. In that regard,each model healthy meniscus is based on the attributes of a specifichealthy meniscus from a cadaver, an average of the attributes of severalhealthy menisci for cadavers with knee components having one or moregeometrical measurements in a similar size range, and/or otherwisederived from data based on the healthy menisci of the cadavers. Further,in some instances the model healthy menisci are associated with thecorresponding geometrical measurements of the knee components and storedin a database such that a specific model meniscus can be selected for apatient based on the geometrical measurements of the patient's kneecomponents compared to those associated with the model menisci.

Referring again to FIG. 2, in the present embodiment, at step 216, thesegmented healthy meniscus is compared to available prosthetic devices.In some instances, this comparison includes comparing the relative sizesand shapes in terms of linear dimensions (such as depths, widths,heights, and/or radii of curvature) in the different sections or regionsof the meniscus; outer surfaces (such as upper and lower contactsurfaces and/or peripheral surfaces); and/or volumes. In someembodiments, each available prosthetic device is given a score orranking based on how well it matches each of the various dimensions ofthe natural meniscus. By combining the scores for each of thedimensions, an overall geometrical matching score is obtained for eachavailable prosthetic device. In that regard, it is understood that thevarious dimensions are weighted in some embodiments to emphasize theimportance of certain dimensions. The importance or weighting of thevarious dimensions is determined by such factors as the patient's age,activity level, weight, body mass index, and/or other factors consideredby the treating medical personnel. In some instances, the weightingfunction is determined by a computer system. In some instances, theweighting function is at least partially based on the answers providedto prompted questions. In other instances, the treating medicalpersonnel manually set the weighting function of the various dimensions.

In that regard, it is understood that the best prosthetic device or aprosthetic device that will obtain the best score for a particulardimension is not necessarily one with the exact same measurements as thenatural meniscus. In some instances, the prosthetic device is between20% larger and 20% smaller than the natural meniscus. In some particularembodiments of the present disclosure the prosthetic device isapproximately the same size or smaller than a natural healthy meniscus.In some embodiments the prosthetic device is generally between about 1%and about 20% smaller in volume than the natural meniscus in its relaxedpre-implantation state. Similarly, in some embodiments of the presentdisclosure the prosthetic device does not match the shape of the naturalmeniscus. For example, FIG. 5 is a diagrammatic perspective view of aprosthetic device 244 for use in replacing a damaged natural meniscusaccording to the present disclosure shown in comparison to thedimensions of a healthy natural meniscus 246. As illustrated, theprosthetic device 244 does not match the dimensions of the naturalmeniscus 246. In some instances, however, the best prosthetic device issubstantially the same size and shape as the natural meniscus.

Referring again to FIG. 2, at step 218 one or more of the best-gradedprosthetic devices is selected for the direct geometrical matchingmethod as a suitable implant for the specific candidate knee. In someembodiments, only a single, best prosthetic device is identified by thegeometrical matching process 206 at step 218. In other embodiments, allof the available prosthetic devices are ranked based on their score ascalculated using the geometrical matching process 206. In yet otherembodiments, all of the prosthetic devices suitable for the candidateknee are identified and the prosthetic devices that are not suitable arediscarded as potential implant options.

As described below, the measurements and comparisons of the patient'sknee and meniscus are performed substantially by electronic or automatedmeans in some embodiments. However, in other embodiments themeasurements are taken manually, directly from CT/MRI scans. Further,these manual measurements may be compared with prosthetic devicemeasurements. The prosthetic device measurements are provided by themanufacturer in some instances. In other instances, the measurements ofthe prosthetic device are obtained manually as well. The manualmeasurements may be utilized to confirm the measurements and comparisonsobtained using the image processing algorithm and matching process or inlieu of the image processing algorithm and matching process.

Referring still to FIG. 2, the correlation parameters-based matchingprocess 208 is utilized in some embodiments. In some instances, thecorrelation parameters-based matching process utilizes dimensionmeasurements based on one or more large-scale studies of patients havinghealthy knees. Generally, the studies consider the dimensions of a largenumber of patients' knees and define “normal” or acceptable ranges forthe dimensions based on various patient factors. In some instances,geometrical relationships or formulas based on the measured dimensionsof the bones and the menisci are determined for each healthy subject.These geometrical relationships or formulas define the correlationparameters utilized for selecting an appropriate prosthetic device insome embodiments of the present disclosure.

Referring now to FIGS. 6-9, shown therein are various views of a kneejoint 280 based on MRI and/or CT scans identifying measurements of theanatomical features of the knee joint. It should be noted that whilethese measurements are described as being based on MRI and/or CT scansin some instances, it is understood that X-ray and/or other imagingtechniques are also used in some instances in the context of the presentdisclosure. Referring more specifically to FIG. 6, a cross-sectional topview of the knee joint 280 identifying various measurements of theanatomical features is provided. In particular, the width of themeniscus as measured in the coronal plane (labeled MW) and the coronaltibia width (labeled TPW) are identified. These parameters are utilizedfor calculating the coronal relation as described below. Further, thetibia medial length (labeled ML) is identified along with the tibiamedial perimeter (labeled TMP). Referring more specifically to FIG. 7, across-sectional top view of the knee joint 280 similar to that of FIG.6, but identifying measurements of other anatomical features isprovided. Specifically, the anterior and posterior meniscus widths(labeled MWA and MWP, respectively) are provided. Also, the medialmeniscus length (labeled MML) and the meniscus perimeter (labeled P) areprovided. Finally, the medial meniscus body width (labeled MMBW) isprovided. Referring to FIG. 8, a cross-sectional sagittal view close-upof the knee joint 280 identifying the medial meniscus height (labeledHcross) is provided. Finally, referring to FIG. 9, a cross-sectionalside view close-up of the knee joint 280 identifying anterior andposterior meniscus heights (labeled HA and HP, respectively) isprovided. It is fully contemplated that additional and/or alternativeviews of the knee joint 280 be provided. In addition, it is fullycontemplated that additional and/or alternative measurements of the kneejoint 280 be provided. For example, the following Table 1 sets forthvarious measurements and corresponding parameter abbreviations that areutilized in some instances in conjunction with aspects of the presentdisclosure.

TABLE 1 Medical Imaging Measurements Region Parameter Description FemurFCW Femur Condyle Width FCWA Anterior Medial Femur Condyle Width FCWPPosterior Medial Femur Condyle Width FW Medial Femur Width FWA AnteriorMedial Femur Width FWP Posterior Medial Femur Width FL Medial FemoralCondyle Length FLM Medial Femoral condyle Length-Medial edge FLL MedialFemoral condyle Length-Lateral edge FA Femoral condyles Area FMA Femoralcondyle Medial Area Tibia TPW Tibialis Plateau Width TPWA TibialisPlateau Anterior Width TPWP Tibialis Plateau Posterior Width MW Tibialisplateau Medial Width MWA Tibialis plateau Anterior Medial Width MWPTibialis plateau Medial Posterior Width ML Tibialis plateau MedialLength MLM Tibialis plateau Medial Length-Medial edge MLL Tibialisplateau Medial Length-Lateral edge TA Tibialis plateau Area TMA Tibialisplateau Medial Area Meniscus (Intact) MMW Medial meniscus Width MMWAAnterior Medial meniscus Width MMWP Posterior Medial meniscus Width MMLMedial Meniscus Length MMLM Medial Meniscus Length-Medial edge MMLLMedial Meniscus Length-Lateral edge MMA* Medial Meniscus effective Area${\;^{*}{In}\mspace{14mu} {some}\mspace{14mu} {instances}},{{MMA}\mspace{14mu} {is}\mspace{14mu} {assumed}\mspace{14mu} {to}\mspace{14mu} {be}\mspace{14mu} {substantially}\mspace{14mu} {elliptical}\mspace{14mu} {and}},{therefore},{{{is}\mspace{14mu} {calculated}\mspace{14mu} {using}\mspace{14mu} {the}\mspace{14mu} {equation}\text{:}\mspace{14mu} {MMA}} = {\frac{\pi}{4} \cdot {MMW} \cdot {MML}}}$

The following Table 2 identifies normal ranges for the variousmeasurements set forth in Table 1 above for each gender and in general.As described below, these normative ranges are utilized in someinstances for selecting an appropriate prosthetic device for a patient.It is understood that more specific ranges are defined in some instancesbased on patient characteristic information. For example, in someinstances the normal ranges are determined by limiting the source dataused to those data points having one or more characteristics similar tothe current patient.

TABLE 2 Normative Knee Dimensions (measured in mm or mm²) DimensionFemale Male General FCW Avg. ± Std. 73.4 ± 3.6 84.2 ± 4.3 78.7 ± 6.7Maximal 79.5 92.6 92.6 Minimum 64.2 71  64.2 FCWA Avg. ± Std. 66.6 ± 4.474.9 ± 6.5 70.7 ± 6.9 Maximal 74.4 85.2 85.2 Minimum 56  57.3 56  FCWPAvg. ± Std. 70.2 ± 4  81.5 ± 4  75.7 ± 6.9 Maximal 79.8 89.1 89.1Minimum 61.9 71.2 61.9 FW Avg. ± Std. 27.3 ± 2.5 30.6 ± 3.3 28.9 ± 3.3Maximal 31.8 38.8 38.8 Minimum 20.1 23.6 20.1 FWA Avg. ± Std. 34.5 ± 3.139.1 ± 4.1 36.7 ± 4.3 Maximal 39.6 45.4 45.4 Minimum 25.8 28  25.8 FWPAvg. ± Std. 24.1 ± 1.7 28.2 ± 2.6 26.1 ± 3  Maximal 28.1 33.8 33.8Minimum 19.5 22.3 19.5 FL Avg. ± Std. 50.2 ± 4.1 54.3 ± 4.8 52.2 ± 4.9Maximal 57.3 63.4 63.4 Minimum 41.6 42.1 41.6 FLM Avg. ± Std. 45.3 ± 4.349.2 ± 4.2 47.2 ± 4.6 Maximal 52.7 56  56  Minimum 36.4 36.4 36.4 FLLAvg. ± Std. 51.8 ± 4.4 57.2 ± 5.1 54.5 ± 5.5 Maximal 59.2 64.4 64.4Minimum 41.9 43.8 41.9 FA Avg. ± Std. 2372 ± 247 3017 ± 274 2685 ± 415Maximal 3021   3514   3514   Minimum 1789   2260   1789   FMA Avg. ±Std. 1222 ± 114 1527 ± 148 1370 ± 202 Maximal 1454   1857   1857  Minimum 973   1086   973   TPW Avg. ± Std. 69.5 ± 3  80.6 ± 3.9 74.9 ±6.5 Maximal 73.8 89.5 89.5 Minimum 61.2 69.3 61.2 TPWA Avg. ± Std. 63.2± 3.5 71.9 ± 4.1 67.3 ± 5.8 Maximal 69.8 81.3 81.3 Minimum 54.5 61.954.5 TPWP Avg. ± Std. 67.6 ± 3.3 78.5 ± 3.9 72.9 ± 6.5 Maximal 74.7 85.785.7 Minimum 58.9 67.7 58.9 MW Avg. ± Std. 28.1 ± 1.4 32.8 ± 2.1 30.4 ±3  Maximal 30.9 36.3 36.3 Minimum 25  27.4 25  MWA Avg. ± Std. 23.8 ±3.3 26.8 ± 3.2 25.3 ± 3.5 Maximal 30.4 32.3 32.3 Minimum 15.6 20.1 15.6MWP Avg. ± Std. 23.9 ± 2.6 27.3 ± 2.7 25.5 ± 3.1 Maximal 29.9 33.7 33.7Minimum 17.9 20.9 17.9 ML Avg. ± Std. 42.4 ± 2.9 47.9 ± 4.2 45.1 ± 4.5Maximal 49.1 55.9 55.9 Minimum 33.5 37.9 33.5 MLM Avg. ± Std. 35.5 ± 3.440.5 ± 4  38.1 ± 4.5 Maximal 46.2 47.6 47.6 Minimum 28.5 31.7 28.5 MLLAvg. ± Std. 45.8 ± 3.3 52.6 ± 4.1 49.1 ± 5  Maximal 53.2 60.8 60.8Minimum 35.4 42.5 35.4 TA Avg. ± Std. 2672 ± 255 3484 ± 347 3065 ± 507Maximal 3095   4301   4301   Minimum 2039   2361   2039   TMA Avg. ±Std. 1283 ± 171 1664 ± 208 1468 ± 268 Maximal 1632   2080   2080  Minimum 852   1128   852   MMW Avg. ± Std. 24.7 ± 2.2 28.7 ± 2.4 26.7 ±3.1 Maximal 30.1 33.2 33.2 Minimum 20.8 21.1 20.8 MMWA Avg. ± Std. 21.3± 2.6 24.3 ± 2.9 22.7 ± 3.1 Maximal 28.3 30.9 30.9 Minimum 16.9 14.814.8 MMWP Avg. ± Std. 23.8 ± 2.8 27.5 ± 2.4 25.6 ± 3.2 Maximal 29.9 31.331.3 Minimum 17.3 22.4 17.3 MML Avg. ± Std. 38.4 ± 2.8  45 ± 3.5 41.6 ±4.5 Maximal 45  52  52  Minimum 27  35.2 27  MMLM Avg. ± Std. 33.1 ± 3.938.6 ± 4.3 35.7 ± 4.9 Maximal 42.6 45.2 45.2 Minimum 21.3 26.6 21.3 MMLLAvg. ± Std. 39.5 ± 2.7 46.2 ± 3.1 42.8 ± 4.4 Maximal 44.6 52.9 52.9Minimum 30.7 35.8 30.7 MMA Avg. ± Std.  749 ± 102 1017 ± 133  878 ± 179Maximal 1050   1244   1244   Minimum 477   646   477   HA Avg. ± Std.5.5 ± 1   6.5 ± 1.2  5.9 ± 1.2 Maximal  7.7  8.8  8.8 Minimum  3.5  4.4 3.5 HP Avg. ± Std.  5.8 ± 1.1  7.2 ± 1.6  6.5 ± 1.5 Maximal  8.1 12.712.7 Minimum 4   4.8 4  HC Avg. ± Std.  5.6 ± 1.1  6.7 ± 1.2  6.1 ± 1.2Maximal  7.7  8.9  8.9 Minimum  3.3  4.4  3.3 Avg. = Average, Std. =Standard deviation

The following Table 3 identifies normative ranges for geometricrelations between some of the various measurements set forth in Tables 1and 2 above for each gender and in general. As described below, thesenormative ranges are utilized in some instances for selecting anappropriate prosthetic device for a patient. It is understood that morespecific ranges are defined in some instances based on patientcharacteristic information. For example, in some instances the normalranges are determined by limiting the source data used to those datapoints having one or more characteristics similar to the currentpatient.

TABLE 3 Normative internal geometric relations within bones and meniscusRatio type Geometric relation General Male Female Width to length ratios$\frac{MMW}{MML}$ 0.64 ± 0.06 0.64 ± 0.06 0.65 ± 0.06 $\frac{MW}{ML}$0.68 ± 0.05 0.69 ± 0.05 0.66 ± 0.05 $\frac{FW}{FL}$ 0.56 ± 0.07 0.57 ±0.07 0.55 ± 0.06 Medial to total width ratios $\frac{MW}{TPW}$ 0.41 ±0.02 0.41 ± 0.02  0.4 ± 0.01 $\frac{MWA}{TPWA}$ 0.37 ± 0.04 0.37 ± 0.040.38 ± 0.04 $\frac{MWP}{TPWP}$ 0.35 ± 0.03 0.35 ± 0.03 0.35 ± 0.03$\frac{FW}{FCW}$ 0.37 ± 0.04 0.37 ± 0.04 0.37 ± 0.03 $\frac{FWA}{FCWA}$0.52 ± 0.02 0.52 ± 0.02 0.52 ± 0.03 $\frac{FWP}{FCWP}$ 0.34 ± 0.03 0.35± 0.03 0.34 ± 0.02 Medial to total area ratios ${\frac{FMA}{FA}\ }^{*}$0.51 ± 0.02 0.51 ± 0.02 0.52 ± 0.02 $\frac{TMA}{TA}$ 0.48 ± 0.04 0.48 ±0.04 0.48 ± 0.04 Middle to anterior posterior ratios $\frac{MW}{MWA}$1.22 ± 0.16 1.25 ± 0.15  1.2 ± 0.17 $\frac{MW}{MWP}$  1.2 ± 0.12 1.21 ±0.12 1.19 ± 0.12 ${\frac{TPW}{TPWA}\ }^{*}$  1.1 ± 0.04 1.13 ± 0.05 1.1 ± 0.04 $\frac{TPW}{TPWP}$   1 ± 0.02 1.03 ± 0.03 1.03 ± 0.02$\frac{FW}{FWA}$  0.8 ± 0.13  0.8 ± 0.16 0.8 ± 0.1 $\frac{FW}{FWP}$  1.1± 0.12  1.1 ± 0.13 1.14 ± 0.1  $\frac{FCW}{FCWA}$  1.1 ± 0.07 1.13 ±0.08  1.1 ± 0.06 $\frac{FCW}{FCWP}$   1 ± 0.03 1.03 ± 0.03 1.05 ± 0.04Middle to medial/lateral ratios $\frac{ML}{MLL}$ 0.92 ± 0.04 0.91 ± 0.040.93 ± 0.04 $\frac{ML}{MLM}$  1.2 ± 0.08  1.2 ± 0.09 1.19 ± 0.08${\frac{FL}{FLL}\ }^{*}$ 0.96 ± 0.04 0.95 ± 0.03 0.97 ± 0.04$\frac{FL}{FLM}$  1.1 ± 0.04 1.11 ± 0.04 1.11 ± 0.04 *Significantdifference was found between male and female (p < 0.05)

The following Table 4 identifies normative ranges for parametricrelations between some of the various measurements set forth in Tables 1and 2 above for each gender and in general. As described below, thesenormative ranges are utilized in some instances for selecting anappropriate prosthetic device for a patient. It is understood that morespecific ranges are defined in some instances based on patientcharacteristic information. For example, in some instances the normalranges are determined by limiting the source data used to those datapoints having one or more characteristics similar to the currentpatient.

TABLE 4 Parametric relations in the knee, in respect to total tibialplateau width (TPW*): C_(GM) Geometric Measure General Male Female TibiaTPWA 0.91 0.89 0.88 TPWP 0.98 0.97 0.96 MW 0.41 0.41 0.40 MWA 0.34 0.330.33 MWP 0.34 0.34 0.34 ML 0.60 0.59 0.61 MLM 0.50 0.50 0.51 MLL 0.660.65 0.65 TA 0.54 0.55 0.54 TMA 0.26 0.26 0.26 Femur FCW 1.05 1.03 1.05FCWA 0.94 0.93 0.93 FCWP 1.03 1.00 1.00 FW 0.39 0.38 0.39 FWA 0.49 0.480.48 FWP 0.35 0.35 0.34 FL 0.69 0.67 0.72 FLM 0.63 0.61 0.66 FLL 0.720.71 0.73 FA 0.48 0.47 0.48 FMA 0.25 0.24 0.25 Meniscus MMW 0.36 0.360.35 MMWA 0.30 0.30 0.30 MMWP 0.34 0.34 0.34 MML 0.55 0.56 0.55 MMLM0.48 0.48 0.48 MMLL 0.57 0.57 0.56 MMA 0.16 0.16 0.15 C_(GM) =Multiplication coefficient, GM = Indicator of a specific geometricmeasure *It should be noted that TPW is measured using a coronal X-rayimage in some instances.

In some instances, a specific imaging protocol is utilized for obtainingthe appropriate images and measurements from a patient. In that regard,a specific MRI protocol will now be described. However, it is understoodthat other MRI protocols and protocols that utilize other imagingsystems are utilized in some instances. First, MRI scans of thepatient's damaged knee and/or healthy knee are taken. In that regard,coronal, sagittal, and axial views are obtained from one or more scans,each view comprising a plurality of slices. Generally, a suitable DICOMviewer, such as the DicomWorks Viewer, is utilized to view the MRIscans. For coronal slices, the treating medical personnel finds the twoextreme slices where the tibia can still be seen and then identifies themiddle slice between the two extreme slices. In instances where there isan even number of slices such that there is not a single middle slice,but rather two slices adjacent to the middle, the slice where the tibiais wider is identified as the middle slice. The frame width (side toside) of the middle slice is measured and saved. Further, two slicespositioned centrally between the middle slice and the tibial edges (oneon each side of the middle slice) are selected, measured, and saved.Where there is an even number of slices such that there is not a singleslice centrally positioned between the middle slice and the tibialedges, the slice that is closer to the middle slice is utilized. Aposterior slice where the curve of the meniscus is visible is alsoselected, measured, and saved.

For sagittal slices, the medial side—the side away from the fibula—isidentified. The medial-most slice (where the tibia is still visible) andthe lateral-most slice (near the bridge where the femoral arcdisappears) are identified, measured, and saved. A middle slicepositioned centrally between the medial-most slice and the lateral-mostslice is identified, measured, and saved. If there is an even number ofslices such that there is not a single middle slice, the slice closer tothe bridge is selected. Two slices positioned centrally between themiddle slice and the edges (one on each side of the middle slice) areselected, measured, and saved. Where there is an even number of slicessuch that there is not a single slice centrally positioned between themiddle slice and the edges, the slice that is closer to the middle sliceis utilized. For axial slices, a proximal-most tibial slice (withoutvisible “white spots” of the condyles) is selected, measured, and saved.Also, a distal-most femoral slice without a middle connector isselected, measured, and saved. Additional slices from these orientationsare selected, measured, and saved in some instances. Further, in someinstances the slices are not measured, but are saved for future useand/or measurement.

In some embodiments, the slices obtained from the MRI are exported to aCAD system, such as SolidWorks, where further anatomical measurementsare obtained. In some instances, each slice is imported to a differentsketch (on the same plane) using the measured width of the slice asdetermined from the DICOM viewer. Referring to FIG. 10, for the coronalslices centerlines are placed on the proximal end of the tibia and onthe distal end of the femur. In some instances, the centerlines arepositioned to lie on top of the peaks of the edges of the bones. Threeparallel lines are then drawn perpendicular to each centerline. In thatregard, two lines are placed at the edges of the femur separated by awidth FCW and a third line is placed at the gradient change seen on themedial distal edge of the femur, the third femoral line separated fromone edge of the femur by a width FW. Similarly, two lines are placed atthe edges of the tibia separated by a width TPW and a third line isplaced at the medial peak of the tibia, the third tibial line separatedfrom one edge of the tibia by a width MW. For the anterior coronalslice, the middle line is placed at the middle of the arc. For themeniscus slice, a vertical centerline is drawn from the tibial peakacross the meniscus. A center point is marked in the middle of thevertical centerline and a horizontal centerline is drawn perpendicularto the vertical centerline through the center point. Further, a line isdrawn between a center of the distal edge of the meniscus and the centerpoint of the coronal meniscus slice, which is separated by a distanceMMW.

Referring to FIG. 11, for the sagittal slices a centerline is placed ontop of the proximal end of the tibia and four parallel lines are drawnsubstantially perpendicular to the centerline. Two lines are drawn atthe edges of the tibia separated by a distance ML and two lines aredrawn at the edges of the femur separated by a distance FL. A line isalso drawn from the middle of both ends of the meniscus separated by adistance MML.

Referring to FIGS. 12 and 13, for the axial slices a spline is drawn ineach slice around the femur and tibia areas. That is, in some instancesa plurality of points representative of the boundaries of the femurand/or tibia areas are identified. The series of points is theninterpolated to define the representative boundaries. A line is drawn onthe femur slice from a central anterior boundary to a central posteriorboundary. A corresponding line is drawn on the tibial slice from acentral anterior boundary to a central posterior boundary. The lines onthe femur and tibial slices interact with the splines. Planar surfaceareas for the lateral tibial area (TA), lateral femoral area (FA),medial tibial area (TMA), and medial femoral area (FMA) are determined.FIG. 14 illustrates an exemplary axial meniscus slice with thecorresponding meniscal measurements discussed above identified.

Referring now to FIG. 15, shown therein is a chart setting forth variouscorrelation parameters according to one aspect of the presentdisclosure. In the illustrated chart, five specific correlationparameters are identified, namely area, width, length, perimeter, andcoronal relation. In other embodiments, a greater or fewer number ofcorrelation parameters are utilized. Additional correlation parametersare discussed below. Each of the correlation parameters is defined byformula or equation comprised of dimensional measurements of the kneejoint. The acceptable ranges for the correlation parameters are based onCT, MRI, and/or other medical imaging of the healthy subject patients oflarge-scale studies in some instances. The area correlation parameter isdefined by the meniscus contact area divided by the tibia medial area,or

$A = {\frac{MA}{TMA}.}$

The width correlation parameter is defined by the average meniscus widthdivided by the medial tibia width, or

${W = \frac{{MW}_{avg}}{TMW}},$

where the average meniscus width is the average of the anterior meniscuswidth and posterior meniscus width, or

${{MW}_{avg} = \frac{{MW}_{A} + {MW}_{P}}{2}},$

The length correlation parameter is defined by the medial meniscuslength divided by the tibia medial length, or

$L = {\frac{MML}{TML}.}$

The perimeter correlation parameter is defined by the meniscus perimeterdivided by the tibia medial perimeter, or

$P = {\frac{MP}{TMP}.}$

The coronal relation correlation parameter is defined by the meniscuscoronal width divided by the tibia coronal width, or

$C = {\frac{{MW}_{C}}{TCW}.}$

The following Table 5 sets forth a listing of correlation parametersthat are utilized in some embodiments of the present disclosure.Generally, one or more of these correlation parameters is utilized inidentifying one or more suitable prosthetic devices for a particularpatient in accordance with the present disclosure. In accordance withthe present disclosure additional and/or alternative correlationparameters based on any of the anatomical measurements identified inTable 1 above may be utilized. Accordingly, the correlation parametersset forth herein are to be considered exemplary and do not necessarilyprovide an exhaustive list of suitable correlation parameters.

TABLE 5 Correlation Parameter Definitions Parameter DefinitionDescription Tibia Medial Area ratio $\frac{MMA}{TMA}*$$\frac{{Medial\_ Meniscus}{\_ Area}}{{Tibialis\_ plateau}{\_ Medial}{\_ Area}}$Tibia Area ratio $\frac{MMA}{TA}*$$\frac{{Medial\_ Meniscus}{\_ Area}}{{Tibialis\_ plateau}{\_ Area}}$Femur Medial Area ratio $\frac{MMA}{FMA}*$$\frac{{Medial\_ Meniscus}{\_ Area}}{{Femoral\_ condyle}{\_ Medial}{\_ Area}}$Femur Area ratio $\frac{MMA}{FA}*$$\frac{{Medial\_ Meniscus}{\_ Area}}{{Femoral\_ condyles}{\_ Area}}$Tibia Medial Width ratio $\frac{MMW}{MW}$$\frac{{Medial\_ Meniscus}{\_ Width}}{{tibialis\_ plateau}{\_ Medial}{\_ Width}}$Tibia Anterior Medial Width ratio $\frac{MMWA}{MWA}$$\frac{{Anterior\_ Medial}{\_ Meniscus}{\_ Width}}{{tibialis\_ plateau}{\_ Anterior}{\_ Medial}{\_ Width}}$Tibia Posterior Medial Width ratio $\frac{MMWP}{MWP}$$\frac{{Posterior\_ Medial}{\_ Meniscus}{\_ Width}}{{tibialis\_ plateau}{\_ Posterior}{\_ Medial}{\_ Width}}$Femur Medial Width ratio $\frac{MMW}{FW}$$\frac{{Medial\_ Meniscus}{\_ Width}}{{medial\_ Femur}{\_ Width}}$Femur Anterior Medial Width ratio $\frac{MMWA}{FWA}$$\frac{{Medial\_ Meniscus}{\_ Width}}{{medial\_ Femur}{\_ Width}}$Femur Posterior Medial Width ratio $\frac{MMWP}{FWP}$$\frac{{Medial\_ Meniscus}{\_ Width}}{{medial\_ Femur}{\_ Width}}$Tibia Total Coronal ratio $\frac{MMW}{TPW}$$\frac{{Medial\_ Meniscus}{\_ Width}}{{Tibialis\_ Plateau}{\_ Width}}$Tibia Anterior Total Coronal ratio $\frac{MMWA}{TPWA}$$\frac{{Anterior\_ Medial}{\_ Meniscus}{\_ Width}}{{Tibialis\_ Plateau}{\_ Anterior}{\_ Width}}$Tibia Posterior Total Coronal ratio $\frac{MMWP}{TPWP}$$\frac{{Posterior\_ Medial}{\_ Meniscus}{\_ Width}}{{Tibialis\_ Plateau}{\_ Posterior}{\_ Width}}$Femur Medial Coronal ratio $\frac{MMW}{FCW}$$\frac{{Medial\_ Meniscus}{\_ Width}}{{medial\_ Femur}{\_ Condyle}{\_ Width}}$Femur Anterior Medial Coronal ratio $\frac{MMWA}{FCWA}$$\frac{{Anterior\_ Medial}{\_ Meniscus}{\_ Width}}{{medial\_ Femur}{\_ Anterior}{\_ Condyle}{\_ Width}}$Femur Posterior Medial Coronal ratio $\frac{MMWP}{FCWP}$$\frac{{Posterior\_ Medial}{\_ Meniscus}{\_ Width}}{{medial\_ Femur}{\_ Posterior}{\_ Condyle}{\_ Width}}$Tibia Medial Length ratio $\frac{MML}{ML}$$\frac{{Medial\_ Meniscus}{\_ Length}}{{tibialis\_ plateau}{\_ Medial}{\_ Length}}$Tibia Medial Length ratio- Medial edge $\frac{MMLM}{MLM}$$\frac{{{Medial\_ Meniscus}{\_ Length}} - {Medial\_ edge}}{{{tibialis\_ plateau}{\_ Medial}{\_ Length}} - {Medial\_ edge}}$Tibia Medial Length ratio- Lateral edge $\frac{MMLL}{MLL}$$\frac{{{Medial\_ Meniscus}{\_ Length}} - {Lateral\_ edge}}{{{tibialis\_ plateau}{\_ Medial}{\_ Length}} - {Lateral\_ edge}}$Femur Width ratio $\frac{MML}{FL}$$\frac{{Medial\_ Meniscus}{\_ Length}}{{medial\_ Femoral}{\_ condyle}{\_ Length}}$Femur Medial Width ratio $\frac{MMLM}{FLM}$$\frac{{{Medial\_ Meniscus}{\_ Length}} - {Medial\_ edge}}{{{medial\_ Femoral}{\_ condyle}{\_ Length}} - {Medial\_ edge}}$Femur Lateral Width ratio $\frac{MMLL}{FLL}$$\frac{{{Medial\_ Meniscus}{\_ Length}} - {Lateral\_ edge}}{{{medial\_ Femoral}{\_ condyle}{\_ Length}} - {Lateral\_ edge}}$$\;^{1}{MMA} = {{{Medial}\mspace{14mu} {meniscus}\mspace{14mu} {calculated}\mspace{14mu} {area}\mspace{14mu} \left( {{oval}\mspace{14mu} {area}\mspace{14mu} {assumption}} \right)} = {{MMA} = {\frac{\pi}{4} \cdot {MMW} \cdot {MML}}}}$

The following Table 6 identifies normal ranges for the variouscorrelation parameters set forth in Table 5 above for each gender and ingeneral. As described below, these normative ranges are utilized in someinstances for selecting an appropriate prosthetic device for a patient.It is understood that more specific ranges are defined in some instancesbased on patient characteristic information. For example, in someinstances the normal ranges are determined by limiting the source dataused to those data points having one or more characteristics similar tothe current patient. Table 6 sets forth the mean and standard deviationfor each correlation parameter based on a large scale study. It iscontemplated that additional large-scale studies may be performed in thefuture and that the accepted ranges for the correlation parametersdiscussed herein below may be adjusted, as necessary, to conform withthe accepted dimensional ranges in the field.

TABLE 6 Normative Knee Geometric Relations Geometric relation FemaleMale General ${\frac{MMA}{TMA}\ }^{1}$ Avg. ± Std. 0.59 ± 0.07 0.62 ±0.08  0.6 ± 0.08 ${\frac{MMA}{TA}\ }^{1}$ Avg. ± Std. 0.28 ± 0.04 0.29± 0.04 0.29 ± 0.04 ${\frac{MMA}{FMA}\ }^{1}$ Avg. ± Std. 0.61 ± 0.080.67 ± 0.08 0.64 ± 0.08 ${\frac{MMA}{FA}\ }^{1}$ Avg. ± Std. 0.32 ±0.04 0.34 ± 0.04 0.33 ± 0.04 $\frac{MMW}{MW}$ Avg. ± Std. 0.88 ± 0.070.88 ± 0.06 0.88 ± 0.07 $\frac{MMWA}{MWA}$ Avg. ± Std.  0.9 ± 0.12 0.91± 0.1  0.9 ± 0.11 $\frac{MMWP}{MWP}$ Avg. ± Std.   1 ± 0.07 1.01 ± 0.09  1 ± 0.08 $\frac{MMW}{FW}$ Avg. ± Std. 0.91 ± 0.1  0.95 ± 0.12 0.93 ±0.11 $\frac{MMWA}{FWA}$ Avg. ± Std. 0.62 ± 0.06 0.62 ± 0.06 0.62 ± 0.06$\frac{MMWP}{FWP}$ Avg. ± Std. 0.99 ± 0.11 0.98 ± 0.1  0.98 ± 0.11$\frac{MMW}{TPW}$ Avg. ± Std. 0.36 ± 0.03 0.36 ± 0.03 0.36 ± 0.03$\frac{MMWA}{TPWA}$ Avg. ± Std. 0.34 ± 0.04 0.34 ± 0.03 0.34 ± 0.04$\frac{MMWP}{TPWP}$ Avg. ± Std. 0.35 ± 0.03 0.35 ± 0.03 0.35 ± 0.03$\frac{MMW}{FCW}$ Avg. ± Std. 0.34 ± 0.03 0.34 ± 0.03 0.34 ± 0.03$\frac{MMWA}{FCWA}$ Avg. ± Std. 0.32 ± 0.03 0.32 ± 0.03 0.32 ± 0.03$\frac{MMWP}{FCWP}$ Avg. ± Std. 0.34 ± 0.03 0.34 ± 0.03 0.34 ± 0.03$\frac{MML}{ML}$ Avg. ± Std. 0.91 ± 0.05 0.94 ± 0.05 0.92 ± 0.06$\frac{MMLM}{MLM}$ Avg. ± Std. 0.95 ± 0.1  0.97 ± 0.09 0.96 ± 0.09$\frac{MMLL}{MLL}$ Avg. ± Std. 0.86 ± 0.05 0.88 ± 0.05 0.87 ± 0.05$\frac{MML}{FL}$ Avg. ± Std. 0.77 ± 0.05 0.83 ± 0.05  0.8 ± 0.06$\frac{MMLM}{FLM}$ Avg. ± Std. 0.73 ± 0.06 0.79 ± 0.06 0.76 ± 0.07$\frac{MMLL}{FLL}$ Avg. ± Std. 0.77 ± 0.06 0.81 ± 0.06 0.79 ± 0.06 Avg.= Average, Std. = Standard deviation, Data is based on large scale humanknee MRI-scans${\;^{1}{MMA}} = {{{Medial}\mspace{14mu} {meniscus}\mspace{14mu} {calculated}\mspace{14mu} {area}\mspace{14mu} \left( {{oval}\mspace{14mu} {area}\mspace{14mu} {assumption}} \right)} = {{MMA} = {\frac{\pi}{4} \cdot {MMW} \cdot {MML}}}}$

In some instances, as discussed above MRI scans of the patient's knee(s)are obtained in order to determine the various measurements associatedwith the patient's knees. In that regard, generally any suitable MRImachine may be utilized. In some instances a 1.5 Tesla or a 3.0 TeslaMRI machine is utilized. Referring to FIGS. 16, 17, and 18, showntherein are three exemplary embodiments of different types of MRI scansthat are utilized in some embodiments of the present disclosure. In thatregard, FIG. 16 illustrates an MRI machine that provides scans with nogaps between imaging slices. FIG. 17 illustrates an MRI machine thatprovides scans with a gap between imaging slices. Finally, FIG. 18illustrates an MRI machine that provides scans with an interleavebetween imaging slices.

Referring again to FIG. 2, the correlation parameters-based matchingprocess 208 begins at step 220 where CT, MRI, and/or medical images ofthe injured knee of a candidate patient are obtained. Based on theimaging of the injured knee, various anatomical measurements of the kneecan be obtained. For example, in some instances it is desirable toobtain information regarding the dimensions of the tibia. In thatregard, the dimensions of the tibia discussed above with respect to thecorrelation parameters (e.g., tibia medial area, tibia medial width,tibia medial length, tibia medial perimeter, tibia coronal width, and/orother tibia dimensions) are obtained in some instances.

The process 208 continues at step 222 where the correlation parametersfor one or more of the available prosthetic devices are determined. Thegeometrical relationship formulas of the correlation parameters arecalculated for the prosthetic device based on the available candidateknee data and compared to the accepted normative data for eachprosthetic device. Each prosthetic device is given a sub-grade for eachcorrelation parameter based on how well the device matches up with theaccepted ranges for that correlation parameters. In that regard, anacceptable range of values for the prosthetic device can be determinedbased the available measurements of the candidate knee and the normativedata (e.g., normative range±standard deviation) for the candidate knee.For example, with respect to the area correlation parameter, theacceptable range of meniscus contact areas for the prosthetic devicescan be determined by multiplying the normative range of acceptable areasby the tibia medial area, or A×TMA=MA. The acceptable ranges for otheraspects of the prosthetic device may be calculated similarly for each ofthe correlation parameters.

The process 208 continues at step 224 where the calculated correlationparameters are compared to the normative or accepted correlationparameters. In some instances, the normative data is selected on afemale, male, and/or general population basis. Depending on how well theprosthetic device fits within the range for each correlation parameter,a sub-grade is determined for that parameter. The better the fit, thebetter the sub-grade for that parameter. In some instances, the gradesare binary. Meaning if the device is within the acceptable range itreceives the best score and if the device is outside of the range itreceives the worst score. Similar to the previous geometrical matchingmethod, the best-graded prosthetic device is calculated by adding up allof the sub-grades to determine an overall grade. In that regard, it isunderstood that the various correlation parameters are weighted in someembodiments to emphasize the importance of certain correlationparameters. The importance or weighting of the correlation parametersare determined by such factors as the patient's age, activity level,weight, and/or other factors considered by the treating medicalpersonnel. In some instances, the weighting function for the correlationparameters is determined by a computer system based on the answersprovided to prompted questions. In other instances, the treating medicalpersonnel manually set the weighting function for the correlationparameters.

Further, it is understood that the correlation parameters may varydepending on the type of implant being considered. For example, in someembodiments of the present disclosure the prosthetic devices aredesigned to be between about 20% larger and about 20% smaller than thenatural meniscus, measured by volume. In some instances, the prostheticdevices are designed to be between about 1% and 20% smaller than thenatural meniscus. Accordingly, such sizing can be taken intoconsideration when determining the acceptable ranges of the dimensionsfor the prosthetic device as they relate to the correlation parameters.At step 226, one or more of the best-graded prosthetic devices isselected for the correlation parameters-based matching process 208 as asuitable implant for the specific candidate knee. In some embodiments,only a single, best prosthetic device is identified by the correlationparameters-based matching process 208. In other embodiments, all of theavailable prosthetic devices are ranked based on their score ascalculated using the correlation parameters-based matching process 208.In yet other embodiments, all of the prosthetic devices suitable for thecandidate knee are identified and the prosthetic devices that are notsuitable are discarded as potential implant options.

The finite element-based matching process 210 is utilized in someembodiments. The finite element-based matching process 210 begins atstep 228 where CT, MRI, and/or other medical images of the injured kneeof a candidate patient are obtained. In some instances, the same CT,MRI, and/or other medical images are utilized for both the finiteelement-based matching process 210 and the correlation parameters-basedmatching 208. Similar to the direct geometrical matching process 206discussed above with respect to the healthy knee joint, at step 230 theinjured knee joint of the patient is segmented into its variouscomponents, such as the bone, articular cartilage, and menisci. In someinstances, a three-dimensional solid geometry model of the bones,cartilage, and menisci of the injured knee is built. Based on the solidgeometry, a patient-specific finite element model of the knee is createdat step 232. The patient-specific finite element model is configured tointerface with various finite element models of prosthetic devices insome instances. In that regard, in some embodiments the finite elementmodel does not include the natural damaged meniscus. Further, in someinstances a finite element model of the patient's healthy knee iscreated for use in evaluating the effectiveness of the prostheticdevices in the injured knee.

The finite element-based matching process 210 continues at step 234where several simulation cases using the finite element model aretested. First, in some embodiments a load of up to 3-times the patient'sbody-weight is applied by the femur on the natural, damaged meniscus. Inother embodiments, the simulation of loading on the damaged meniscus isomitted. In other embodiments, a simulation of loading of the naturalmeniscus of the patient's healthy knee is performed and utilized as abase line. Regardless of whether a damaged or healthy meniscus isutilized, peak and average pressure measurements across the meniscus,peak and average pressure measurements acting on the femoral and tibialarticular cartilage, pressure distributions across the tibialis plateau,and/or other measurements are calculated.

Step 234 also includes testing one or more available prosthetic devicesunder a simulated load. Referring to FIG. 19, shown therein is athree-dimensional finite element model 290 of a knee joint 292 with aprosthetic device 294 positioned between a tibialis plateau 296 and afemur 298 according to one aspect of the present disclosure. For each ofthe available prosthetic devices, peak and average pressure measurementsacross the prosthetic device, peak and average pressure measurementsacting on the femoral and tibial articular cartilage, pressuredistributions across the tibialis plateau, and/or other measurements arecalculated. Referring to FIG. 20, shown therein is a simulated contactpressure map 300 for the prosthetic device 294 of FIG. 19 illustratingcontact pressures between the prosthetic device and the tibialis plateau296.

At step 236, the resultant simulated pressure measurements for each ofthe prosthetic devices are compared to medically accepted values and/orthe natural, healthy meniscus to provide the prosthetic devices withsub-grades for each of the measurements. For example, the peak pressuremeasurements of each of the prosthetic devices are compared to theaccepted ranges or the peak pressure measurements of the natural,healthy meniscus. The extent to which the prosthetic device is withinthe accepted range determines the device's sub-grade for peak pressure.Similarly, the peak and average pressure acting on the articularcartilages are compared to the allowed natural values for eachprosthetic device and the prosthetic device is given sub-gradesaccordingly. Further, the tibialis plateau pressure distributions foreach prosthetic device are compared to those of a healthy naturalmeniscus in terms of contact area size and stress concentrations. In oneparticular embodiment, a prosthetic device is given a perfect sub-gradescore if the resultant pressure distribution across the tibialis plateauis within ±15% of a healthy natural meniscus.

In some instances, the contact pressures are compared to accepted valuesfor a healthy natural meniscus based on one or more large scale studies.In some large scale studies the contact pressures of intact healthymenisci are measured in human cadaveric knees under load. Referring toFIG. 21, in some instances healthy knees are positioned on a jig formechanical compression testing. With the cadaver knee positioned withinthe jig, all degrees of freedom of the knee are fixed to preventunwanted flexion of the knee during the compression test. Also, in someinstances the MCL bone plug is released to allow for the insertion ofone or more contact pressure sensors. Generally, any suitable contactpressure sensors are utilized. In some instances, pressure sensorsavailable from Tekscan Inc. are utilized. With the healthy medialmeniscus intact, the knee is subjected to a load at a flexion angle of0°. In some instances, the maximum load is between about 800N and about2000N. In some instances, the maximum load is approximately 1200N. Insome embodiments, the amount of load applied to the knee is controlledthrough a software interface and may vary from about 1N to about 2000N.In some instances, the amount of load applied is at least partiallybased on the patient's weight and/or activity level.

Corresponding pressure maps are obtained from the pressure sensors basedon the loading of the knee and, in particular, the meniscus. Thepressure maps are displayed via a software interface in someembodiments. In some instances, the same software interface (orcoordinated software interfaces) is utilized for both controlling theamount of load applied to the knee and displaying the correspondingpressure maps. The pressure maps are stored in an accessible database insome instances. In that regard, the pressure maps may be associated withcharacteristics of the knee being tested (such as tibial, femoral, andmeniscal dimensions and/or other characteristics) and/or patientcharacteristics (such as weight, activity level, and/or othercharacteristics) such that the pressure maps and associated data may beretrieved for use in future prosthetic device selection methods.

As discussed in greater detail below, similar loading and pressuremonitoring methods are utilized in some embodiments of the presentdisclosure for trialing prosthetic devices during a surgical procedurein order to identify the best prosthetic device for the patient. In thatregard, trial prosthetic devices containing pressure sensors areintroduced into the patient's knee and the knee is subjected to a load.The corresponding pressure maps of the trial prosthetic devices are thencompared to those of a healthy meniscus (based on a cadaver study orotherwise) and/or accepted values for a healthy meniscus to determinethe suitability of the prosthetic device.

In that regard, in some instances the pressure distribution mapsattained from the trial prosthetic devices are analyzed and compared tothe pressure distribution maps attained from one or more cadavericknees. The pressure distribution maps are analyzed and compared on aregional basis, a global basis, or a combination thereof. In someinstances, a comparison of local or regional characteristics isadvantageous in identifying small, but possibly critical variations inthe pressure maps and/or in emphasizing regions of interest.Furthermore, measurement of the total contact area on a global basisand/or global contact pressures may not reveal potentially problematicdiscrepancies in the contact areas and pressure points of the prostheticdevices. Quantization of the small regional areas better approximatesthe specific shape of the contact areas and the maximum pressure pointsin some instances. Based on the shape of the natural meniscus, thepressure maps are divided into 9 regions in some embodiments. Forexample, FIG. 22 illustrates one embodiment of a pressure map showndivided into the 9 separate rectangular regions. In other instances, thepressure maps are divided into other numbers of regions and/or regionshaving shapes other than rectangular. For the purposes of thisdisclosure the 9 rectangular regions will be utilized with it beingunderstood that other orientations are utilized in some instances andthat any comparisons, weightings, equations, or otherwise are modifiedto correspond with the alternative regional orientations in suchinstances.

In some instances, the pressure distributions or pressure maps of thetrial prosthetic devices are compared to the accepted pressuredistributions for a healthy meniscus. In some instances, the prostheticdevices are scored based on how well each device's pressure map comparesto the accepted pressure distributions. In one embodiment, 3 differentmeasurements are utilized to evaluate the pressure maps of theprosthetic devices: global contact area, regional contact area, and peakregional pressures. The first measurement is the global contact area orutilization of area determination, where the total contact area of theprosthetic device under load is compared to the established value fortotal contact area of a healthy meniscus. In some instances, thisdetermination is based on a binary function where the prosthetic deviceis given a full score (e.g. 1) if the total contact area is within acertain percentage of the accepted value. In that regard, in someinstances the acceptable percentage variation is between about ±30%. Insome instances, the acceptable percentage variation is between about±20%. In other instances, the acceptable percentage variation is betweenabout ±10%. In some instances, the acceptable percentage variation isselected by the treating medical personnel. A binary equation isutilized to quantify this determination in some instances. For example,the following binary equation is based on a ±30% acceptable percentagevariation:

${{Bin}\left\{ x \right\}} = \left\{ \begin{matrix}{1,{{{if}\mspace{14mu} 0.7} < x < 1.3}} \\{0,{{otherwise}.}}\end{matrix} \right.$

Similar, binary equations are utilized for other percentage variations.For example, a ±15% acceptable percentage variation is represented bythe following binary equation in some instances:

${{Bin}\left\{ x \right\}} = \left\{ \begin{matrix}{1,{{{if}\mspace{14mu} 0.85} < x < 1.15}} \\{0,{{otherwise}.}}\end{matrix} \right.$

Based on the binary equation corresponding to the acceptable percentagevariation of the contact areas a utilization of area score or globalcontact score is determined. In some instances, the utilization of areais weighted to be a certain percentage of the overall score of theprosthetic device. For example, in some instances the utilization ofarea is weighted to be between 0% and 50% of the prosthetic devicesoverall score. In one particular embodiment, the following equationrepresents the utilization of area (“UoA”) score:UoA=6.6·Bin{AoC(I)/Aoc(M)}, where AoC represents the total contact areafor the implant (I) and natural meniscus (M). Similar equations areutilized for other weightings by changing the value of the numbermultiplied by the binary function to give effect to the desiredpercentage of the overall score.

Generally, the regional contact area parameter is determined, scored,and weighted in a manner similar to that of the global contact areadiscussed above. For example, in some instances a contact area (CA)score is determined by the following equation:

${{CA} = {\sum\limits_{n = 1}^{9}{{w_{n} \cdot {Bin}}\left\{ \frac{A_{n}^{I}}{A_{n}^{M}} \right\}}}},$

where A^(I) _(n) and A^(M) _(n) represent the contact areas for theimplant and natural meniscus, respectively, and w_(n) represents theweight factor of each region n. In one particular embodiment, the weightfactors for the regions 1-9 as illustrated in FIG. 22 are as set forthin the following Table 7:

TABLE 7 Exemplary Contact Area Weight Function Values region 1 2 3 4 5 67 8 9 w_(n) 0.66 0.99 0.66 0.99 0.66 0.99 0.33 0.33 0.99

Peak contact pressure for each of the regions is also considered in someembodiments. In some instances, the peak contact pressure for eachregion is compared to the accepted peak contact pressure for a healthymeniscus. In other instances, the ratio of the peak contact pressure tothe average contact pressure for each region is compared to the acceptedratio of peak contact pressure to average contact pressure. For example,in one embodiment, the peak contact pressure score (PCP) is determinedby the following equation:

${{PCP} = {\sum\limits_{n = 1}^{9}{{q_{n} \cdot {Bin}}\left\{ \frac{{PP}_{n}^{I}/{PA}_{n}^{I}}{{PP}_{n}^{M}/{PA}_{n}^{M}} \right\}}}},$

where PP^(I) _(n) and PP^(M) _(n) represent the peak contact pressure inregion n for the implant and healthy natural meniscus, respectively,where PA^(I) _(n) and PA^(M) _(n) represent the average contact pressurein region n for the implant and natural meniscus respectively, and whereq_(n) represents the weight factor of region n. In one particularembodiment, the weight factors for the regions 1-9 as illustrated inFIG. 22 are as set forth in the following Table 8:

TABLE 8 Exemplary Peak Contact Pressure Weight Function Values region 12 3 4 5 6 7 8 9 q_(n) 0.68 1.02 1.02 0.68 0.68 1.02 0.34 0.34 1.02

In some instances, the score of the prosthetic device is determined byadding the scores for the utilization of area, contact area, and peakcontact pressure together. In some instances, one or more additionalparameters are taken into consideration in scoring the prostheticdevices. For example, in some instances a binary implant movement ordislocation score (IM) is utilized. In that regard, if unwanted movementor dislocation of the prosthetic device occurs during trialing of theprosthetic device, then the prosthetic device is given a score of zero.However, if no unwanted movement or dislocation occurs, then theprosthetic device is given a score of one. In some instances, a binaryimplant impingement score (CP) is utilized. In that regard, if theprosthetic device impinges on any cruciate ligaments or othersurrounding anatomy that will be detrimental to the performance of theprosthetic device, then the prosthetic device is given a score of zero.However, if no such impingement occurs, then the prosthetic device isgiven a score of one. In some instances, the score of the prostheticdevice takes into account both the implant movement or dislocation score(IM) and the implant impingement score (CP). In one particular example,the following equation represents the total score of the prostheticdevice taken these additional parameters into account:

SCORE=(UoA+CA+PCP)·IM·CP

Referring now to FIG. 23, shown therein is are three pressure maps 302,304, and 306 corresponding to a healthy natural meniscus, a best matchedprosthetic device based on the healthy natural meniscus, and a lesssuitable or unsuitable prosthetic device based on the healthy naturalmeniscus, respectively. As noted on the pressure map 302, the healthynatural meniscus has a score of 100 or a perfect score. This is becausereplicating the healthy natural meniscus is the goal of the prostheticdevices. In some instances, the pressure map 302 or goal is based on anaccepted pressure distribution that is derived from one or more healthynatural menisci. As shown, the prosthetic device of pressure map 304 hasa score of 81, whereas the prosthetic device of pressure map 306 has ascore of 39. While generally the highest score possible is preferred, insome instances a threshold score (e.g., 70 points on a 100 point scale)is utilized to determine whether a particular prosthetic device issuitable for a patient. If the prosthetic device meets or exceeds thethreshold score, then it is further considered. In that regard, wheremultiple prosthetic devices meet or exceed the threshold score, each ofthe suitable prosthetic devices are trialed or otherwise tested in someinstances to identify the most suitable device for the patient.

Referring again to FIG. 2, in some instances the simulated loading ofthe prosthetic devices at step 234 and the corresponding evaluation ofthe resultant pressure maps at step 236 are scored using the same orsubstantially similar parameters as those discussed above. In otherinstances, other parameters and/or scores are utilized. Generally, bycombining the scores for each factor of the loading simulations, anoverall score is obtained for each available prosthetic device. In thatregard, it is understood that the various factors or measurements areweighted in some embodiments to emphasize the importance of certainaspects of the prosthetic device. The importance or weighting of thevarious factors are determined by such factors as the patient's age,activity level, weight, and/or other factors considered by the treatingmedical personnel. In some instances, the weighting function isdetermined by a computer system based on the answers provided toprompted questions. In other instances, the treating medical personnelmanually set the weighting function of the various dimensions.

In some instances, the finite element-based matching process 210includes motion simulations in addition to or in lieu of the loadbearing simulations discussed above. In that regard, the motion of theknee joint is compared to that of natural, healthy meniscus for one ormore available prosthetic devices. In some instances, these simulationsare designed to simulate typical patient movements such as walking,running, riding a bicycle, standing up, sitting down, etc. Theprosthetic devices are then provided sub-grades based on theirperformance for various factors related to knee movement (e.g., positionand/or loading support at various degrees of flexion). In someembodiments, the loading simulations and motion simulations are combinedsuch that the devices are scored base on loading functions during themotion simulations.

In some instances, the finite element-based matching process is comparedto a generic model rather than a patient specific model. For example, insome embodiments a plurality of finite element models are providedcorresponding to variety of different knee sizes and/or knee types. Aspecific finite element model from the plurality of different finiteelement models is selected for the current patient. In some embodiments,the specific finite element model is based at least partially on theknee size of the current patient. In one instance, the selected model isdetermined based on MRI data of the patient. Further, in some instancesthe selection of the specific finite element model is at least partiallybased on correlation parameters—such as those discussed above withrespect to the correlation-based matching process 208—for the candidateknee. In some instances, each of the available prosthetic devices istested or simulated with respect to each of the finite element modelsand the functionality of each of the prosthetic devices is compared tothe accepted values for a natural, healthy meniscus. Accordingly, foreach of the finite models one or more suitable prosthetic devices areidentified. Thus, using only the associated bone measurements from theCT and/or MRI scans of a candidate knee, a best-matched finite elementmodel is identified and, from the best-matched finite element model, thecorresponding suitable prosthetic devices are identified as suitabledevices for the current patient. Based on the evaluation at step 236,one or more best-fitted prosthetic devices are identified at step 238.

In some embodiments, the pre-implantation matching method 202 continuesat step 240 by weighting the answers provided by the direct geometricalmatching process 206, the correlation parameters-based matching process208, and the finite element-based matching process 210. In someembodiments, each of the matching processes 206, 208, and 210 are givenequal weight. However, in other embodiments the matching processes 206,208, and 210 are given unequal weights. For example, where a genericfinite element model has been utilized—rather than a patient-specificgenerated finite element model—the finite element model-basedcorrelation may be given less weight than the direct geometricalmatching process 206 and the correlation parameters-based matchingprocess 208. The determination of the weighting of the differentmatching processes 206, 208, and 210 is determined by the treatingmedical personnel in some instances.

Table 9 below illustrates one possible scoring breakdown according tothe present disclosure.

TABLE 9 Exemplary Scoring Breakdown Injured knee measurements Intactknee measurements 3D comparisons (2.3.1.) (2.3.2.) (2.3.3.) SideCandidate knee Healthy knee or Accepted Value Healthy knee or AcceptedValue Method MRI measurements MRI measurements Solid modeling* MeasureTPW MW ML TMA FW FL MMWA MMWP MML HA HP HC Volume Shell InterferenceVisual Score 6 points 6 points 4 points Total 16 points

As shown, the scoring includes three categories: injured kneemeasurements, intact knee measurements, and 3D comparisons. In thepresent embodiment, the injured and intact knee measurements eachaccount for 6 points and the 3D comparisons account for 4 points, for atotal possible score of 16 points for any prosthetic device. In thatregard, for the injured knee measurements the prosthetic device isscored on a scale from 0 to 1.0 for each of 6 different parameters. Inthe present embodiment, at least six measurements of the injured kneeare taken, namely TPW, MW, ML, TMA, FW, and FL, each of which isdiscussed above. Based on these measurements, each prosthetic device isscored for each of the six different parameters. In the presentembodiment, the six parameters are MMW/TPW, MMW/MW, MML/ML, MMA/TMA,MMW/FW, and MML/FL, where the numerator is a value of the prostheticdevice and the denominator is the measured value of the injured knee. Inother embodiments, other combinations of measurements and/or scoringparameters, including additional or fewer measurements and/or scoringparameters, are utilized. In some instances, the scoring for eachparameter is binary. That is, the prosthetic device is either suitablefor the particular parameter (in which case it receives a score of 1) ornot suitable (in which case it receives a score of 0). In someinstances, the determination of whether a prosthetic device is suitablefor a particular parameter is determined by whether the device is withinan accepted range for the parameter. In some instances, the acceptedrange is defined by a standard deviation around an established value forthe parameter. The scores for each of the six parameters are addedtogether to arrive at the injured knee measurement sub-score.

For the intact or healthy knee measurements the prosthetic device isscored on a scale from 0 to 1.0 for each of 6 different measurements. Inthe present embodiment, the six measurements are MMWA, MMWP, MML, HA,HP, and HC, each of which is discussed above. In other embodiments,other combinations of measurements, including additional or fewermeasurements, are utilized. The measurements of the prosthetic deviceare directly compared to these measurements of the healthy knee and theprosthetic device is scored accordingly. In that regard, for each of themeasurements the prosthetic device is scored on a scale from 0 to 1.0.In some instances, the scoring for each measurement or parameter isbinary. That is, the prosthetic device is either suitable for theparticular measurement (in which case it receives a score of 1) or notsuitable (in which case it receives a score of 0). The scores for eachof the six measurements are added together to arrive at the intact kneemeasurement sub-score.

Finally, for the 3D modeling comparisons each prosthetic device isscored on a scale from 0 to 1.0 for each of 4 different parameters. Inthe present embodiment, the four parameters are volume, shell,interference, and visual. Generally, a 3D model of both the prostheticdevice and the healthy intact meniscus are utilized in the 3D modelingcomparisons. However, in some instances no actual 3D models aregenerated, but the corresponding measurements are utilized for makingthe comparisons. In that regard, the volume parameter compares thevolume of the prosthetic device to the volume of the intact healthymeniscus. The closer the match in the volume the higher the score forthe prosthetic device. Similarly, the shell volume compares the outersurface of the prosthetic device to the outer surface of the intactmeniscus. The closer the match in the outer surfaces the higher thescore for the prosthetic device. The interference parameter looks to theoverlap between the prosthetic device and the intact meniscus. That is,the interference parameter looks to identify how well the prostheticdevice matches up the volume defined by the intact meniscus. The closerthe prosthetic device matches the healthy meniscus, the higher thescore. Finally, in some instances a visual comparison of the prostheticdevice to the healthy or intact meniscus is performed. In that regard,treating medical personnel makes an educated determination of how wellthe prosthetic device matches the meniscus. In some embodiments, othercombinations of measurements and/or parameters, including additional orfewer measurements and/or parameters, are utilized. For example, in someembodiments, the subjective or qualitative visual comparison is notperformed and/or not included in the scoring of the prosthetic device.For each of the comparisons, the prosthetic device is scored on a scalefrom 0 to 1.0. In some instances, the scoring for each comparison orparameter is binary. That is, the prosthetic device is either suitablefor the particular parameter (in which case it receives a score of 1) ornot suitable (in which case it receives a score of 0). The scores foreach of the comparisons are added together to arrive at the 3Dcomparison sub-score.

With each of the injured knee sub-score, the intact knee sub-score, andthe 3D comparison sub-score calculated, a total score for eachprosthetic device is determined by adding the sub-scores together.Generally, the prosthetic device with the highest total score will beidentified as the best suited prosthetic device. However, as discussedabove, in some instances more than one prosthetic device is identifiedas being suitable (e.g., meeting a threshold score), in which caseadditional scoring or trialing of the suitable prosthetic devices isutilized to select the best suited prosthetic device.

Finally, the pre-implantation matching method 202 continues at step 242with the identification of one or more suitable prosthetic devices areidentified. In some embodiments, a single “best” prosthetic device isidentified by the pre-implantation matching method 202. In otherembodiments, two or more suitable prosthetic devices are identified. Inthat regard, where two or more suitable prosthetic devices areidentified a specific prosthetic device is selected by theduring-implantation matching process 204.

Referring now to FIGS. 1 and 24, after the pre-implantation matchingprocess at step 202, the method 200 continues at step 204 with aduring-implantation matching process. The during-implantation matchingprocess 204 begins at step 310 with the selection of at least twosuitable trial prosthetic devices. In some embodiments, the suitabletrial prosthetic devices are identified by the pre-implantation matchingprocess 202 described above. In some embodiments, three trial prostheticdevices are selected. Further, in one particular embodiment threedifferent sizes of a prosthetic device are selected. In otherembodiments, the selected prosthetic devices may be substantiallydifferent in shape, materials, function, and/or other properties. Insome embodiments, the trial prosthetic devices are substantially similarto the prosthetic devices that are to be permanently implanted. In someembodiments, the trial implants are the actual prosthetic devices thatare to be permanently implanted. In one embodiment, each trial has asimilar external geometry to the final implant and is formed of amaterial having similar strength properties to the final implant.However, the trial lacks the reinforcing fibers or layer. Thus, thetrial may be more easily removed from the knee joint than the finalimplant. Further, in some instances, the trial includes a visualindicator such as a marking (e.g., “TRIAL”) on the exterior or a dye inthe polymer resin to readily distinguish the trial from the finalimplant. In some instances, the trials include radiopaque markersimbedded therein to distinguish them from the final implant.

The during-implantation matching process 204 continues at step 312 withan in viva physical testing of the prosthetic device. Generally, the invivo testing comprises introducing the trial prosthetic device into theknee joint and moving the knee joint through a series of movements. Atstep 314, the surgeon considers the fit of each prosthetic device trialand the corresponding movement of the knee joint. Based on the surgeon'sobservations at step 314, the during-implantation matching process 204concludes at step 316 with the final selection of the best prostheticdevice for the patient. Subsequently, the surgeon implants the selectedprosthetic device into the patient. In some instances, the prostheticdevice is implanted according to methods described herein.

Utilizing the during-implantation matching process 204, the surgeon candecide, based on actual physical tests, which prosthetic device bestfits a candidate knee. In that regard, in some embodiments thepre-implantation matching process is utilized to identify two or moreprosthetic devices that are suitable for use in the candidate knee. Theduring-implantation matching process is then utilized to select the bestof the suitable prosthetic devices. Accordingly, the during-implantationmatching process 204 may be utilized to confirm the results of thepre-implantation matching process 202 in some instances. In someembodiments, trial implants are utilized in the during-implantationmatching process for selecting the appropriate sized prosthetic deviceand then the actual prosthetic device of that size is subsequentlyimplanted. In some embodiments, three sizes of prosthetic devices and/ortrials are taken to surgery. Typically, the three sizes will be the bestfit prosthetic device identified in the pre-implantation matchingprocess, and prosthetic devices slightly larger and slightly smallerthan the best fit device. According to the fit within the actualcandidate knee the surgeon identifies the best prosthetic device to use.After identifying the best fit prosthetic device during surgery, thesurgeon implants the surgical device.

Referring now to FIG. 25, shown therein is a block diagram of a surgicalprotocol 320 according to one aspect of the present disclosure.Generally, the surgical protocol 320 relates to the implantation of aprosthetic device into the knee joint of a patient. In the specificallydescribed embodiments, the surgical protocol 320 relates to theimplantation of a surgical device for replacing a medial meniscus. Inother embodiments, similar surgical protocols are utilized for replacinga lateral meniscus with a surgical device. In some instances, thesurgical procedure replaces both the medial and lateral menisci withprosthetic devices.

The surgical protocol 320 begins at step 322 where an arthroscopy isperformed. In some embodiments, a leg holder or post is utilized. Insuch embodiments, the leg holder or post may be utilized in subsequentsteps to facilitate application of a valgus force, ease insertion ofimplant, and/or otherwise assist in the performance of the surgery. Thearthroscopy is a routine arthroscopy in some embodiments. The surgicalprotocol 320 also addresses any additional inter-articular pathologiesas needed at step 322.

The surgical protocol 320 continues at step 324 with an evaluation ofthe articular cartilage of the knee joint. In some embodiments, theintegrity of the articular cartilage positioned within the medialcompartment is evaluated. Generally, the evaluation of the articularcartilage is to confirm that the patient's knee is suitable forreceiving the prosthetic device intended to be implanted. In someinstances, the articular cartilage is evaluated to identify defects inthe articular cartilage such that these defects may be treated orotherwise addressed prior to implantation of the prosthetic device.

The surgical protocol 320 continues at step 326 where the meniscus andthe fat pad are excised. In that regard, in some embodiments themeniscus is entirely removed (total meniscectomy). In other embodiments,the meniscus is partially removed (partial meniscectomy) to allow forthe introduction of the prosthetic device into the knee joint.Generally, the fat pad is excised only to the degree necessary forexposure or access to the meniscus and/or medial compartment of the kneejoint. Accordingly, in some instances the fat pad remains substantiallyintact. In other embodiments, a substantial portion of the fat pad maybe removed.

The surgical protocol 320 continues at step 328 with an enlarging of themedial portal. Generally, the medial portal is the same portal createdby the arthroscopy of step 322. However, in some embodiments the medialportal is separate from the portal created by the arthroscopy. In someembodiments, the incision is adjacent to the medial border of thepatellar tendon. The medial portal is enlarged to accommodate theinsertion of the prosthetic device or implant into the knee joint. Insome embodiments, the incision or portal is enlarged to a size betweenapproximately 4.0 cm and approximately 6.0 cm. However, depending on thesize of the implant, the flexibility of the implant, and/or otherfactors, the size of the opening may be larger or smaller in otherinstances.

The surgical protocol 320 continues at step 330 with accessing themedial cavity of the knee joint. In some instances, accessing the medialcavity comprises opening the capsule and retinaculum to provide accessto the medial cavity. Further, in some instances any remaining portionsof the anterior meniscus rim are removed or excised when gaining accessto the medial cavity.

After gaining access to the medial cavity, the surgical protocol 320continues at step 332 with the insertion of one or more trial implantsinto the knee joint. The trial implants may represent different sizes ofthe same implant, different types of implants, and/or combinationsthereof. In some embodiments, the trial implants are identified in apre-implantation matching or selection method. In one particularinstance, the pre-implantation matching process 202 discussed above isutilized to identify one or more suitable implants for which trialversions of the implant may be obtained. In some instances, the trialimplants are substantially similar in size and shape to the actualimplant that will be permanently implanted in the patient. In someinstances, the only difference between the trial implant and the actualimplant is the material from which the implant is made. Specifically, inone embodiment, the trial does not include reinforcing fibers. In someinstances, the trial implant and the actual implant are identical copiesof one another. In some instances, a single implant is used as both thetrial and actual implant.

Generally, a first trial implant is inserted into the knee joint. Insome instances, the first trial implant is representative of the implantidentified as the most suitable implant in a pre-implantation selectionprocess. After insertion of the trial implant into the knee joint, thefunctionality of the knee joint is checked. In that regard, the surgeonor other medical personnel moves the knee through a variety of motionssimilar to the natural motions of the knee and monitors the knee forsigns of problems. For example, in some instances the knee is monitoredfor limited or excessive ranges of motion, abnormal sounds (e.g.,clicking or grinding), non-smooth movements, implant rotation, implanttranslation, and/or other issues indicating a potential problem withusing the associated implant. If a problem or potential problem isobserved when checking the functionality of the knee, the first trialimplant is removed, an alternative trial implant is inserted, and kneefunctionality is checked. In some instances, the subsequent trialimplant will be one size up or down from the previous trial implant.Further, the time period for the trialing of the implant can range froma couple of minutes up to several weeks. This process repeats until asuitable trial implant is identified. In some instances, the trialimplant process is substantially similar to the during-implantationmatching process 204 discussed above. In some instances, the knee jointwith the trial implant positioned therein is subjected to a loadsimulating a loading of the knee joint. For example, the loadingsimulates the load associated with standing, walking, jogging,bicycling, and/or otherwise. Exemplary methods of such loading arediscussed in greater detail below. Generally, the simulated loading isutilized to identify the most suitable implant.

After a suitable trial implant has been identified, the surgicalprotocol 320 continues at step 334 with the implantation of the implantor prosthetic device selected during the trialing process. Generally,the prosthetic device is implanted using any suitable implantationmethod for the associated prosthetic device. A couple of implantationmethods will now be described. In some instances, the prosthetic devicesof the present disclosure are suitable for implantation using thefollowing methods. Referring to FIG. 26, shown therein is a blockdiagram of a method 340 of implanting a prosthetic device into apatient's knee according to one aspect of the present disclosure. Insome instances, the method 340 is utilized as the implantation step 334of the surgical protocol 320. The method 340 will be described withrespect to a “floating” implant, i.e., an implant that does notpenetrate the bone or mate with a device that penetrates bone. However,in other instances a similar method may be utilized with an implant thatis fixedly secured to bone by penetrating bone or mating with a devicethat penetrates the bone.

The method 340 begins at step 342 where the patient's knee is fullyflexed. That is, the patient's knee is put in full flexion. After thepatient's knee has been fully flexed, the method 340 continues at step344 where the prosthetic device is positioned onto the medialcompartment of the tibia. In one embodiment a bridge of the prostheticdevice is folded slightly inward into a reduced size insertionconfiguration as it is passed into the knee joint. Once the bridge ofthe prosthetic device reaches the femoral notch, the bridge resilientlymoves to its anchoring configuration. The method 340 continues at step346 where the posterior rim or edge of the prosthetic device ispositioned within the gap between the femur and the tibia adjacent theposterior portion of the femur. With the prosthetic device positioned onthe medial compartment and the posterior rim in the gap between thefemur and tibia, the method 340 continues at step 348 where the knee isextended and a valgus force is applied to the knee. In some instances,the knee is extended to about a 30 degree flexion. In other instances,the knee is extended less or more. This secures the implant within theknee joint and engages the implant with both the medial compartment ofthe tibia and the femur. Subsequently, the shape of the implant and thecompression forces applied across the implant keep the implant in placewithin the knee. In some instances, prosthetic devices as described inthe present disclosure and/or prosthetic devices as described in U.S.patent application Ser. No. 10/497,897 filed Dec. 3, 2002 and titled“Cushion Bearing Implants for Load Bearing Applications”, U.S. patentapplication Ser. No. 11/868,254 filed Oct. 5, 2007 and titled “MeniscusProsthetic Device”, U.S. patent application Ser. No. 12/100,059 filedApr. 9, 2008 and titled “Tensioned Meniscus Prosthetic Devices andAssociated Methods”, and/or U.S. patent application Ser. No. 12/100,069filed Apr. 9, 2008 and titled “Meniscus Prosthetic Devices withAnti-Migration Features”, each of which is hereby incorporated byreference in its entirety, are implanted using the method 340.

Referring now to FIG. 27, shown therein is a block diagram of a method350 of implanting a prosthetic device into a patient's knee according toone aspect of the present disclosure. In some instances, the method 350is utilized as the implantation step 334 of the surgical protocol 320.The method 350 will be described with respect to a “floating” implant,i.e., an implant that does not penetrate the bone or mate with a devicethat penetrates bone. However, in other instances a similar method maybe utilized with an implant that is fixedly secured to bone bypenetrating bone or mating with a device that penetrates the bone.

The method 350 begins at step 352 where a traction suture is inserted.In some instances the traction suture is inserted to theposterior-medial side of where the prosthetic device will be positionedand extends through the posterior-medial soft tissue structuresenveloping the knee. In other embodiments, the traction suture isotherwise positioned adjacent and/or within the knee joint to assist ininsertion of the prosthetic device into the medial cavity. It should benoted that in some instances the traction suture is inserted after apartial insertion of the prosthetic device into the knee joint. Themethod 350 continues at step 354 where the patient's knee is fullyflexed. That is, the patient's knee is put in full flexion. After thepatient's knee has been fully flexed, the method 350 continues at step356 where the prosthetic device is positioned onto the medial condyle ofthe tibia. The method 350 continues at step 358 where the posterior rimor edge of the prosthetic device is positioned within the gap betweenthe femur and the tibia adjacent the posterior portion of the femur.With the prosthetic device positioned on the medial condyle and theposterior rim in the gap between the femur and tibia, the method 350continues at step 360 where the knee is extended and a valgus force isapplied to the knee. The method 350 continues at step 362 where theimplant is pulled into its final position while applying tension withthe traction suture. In some instances, the traction suture helpsfacilitate positioning of the implant. In some embodiments, the tractionsuture is utilized to urge the implant into the medial cavity. In otherembodiments, the traction suture is utilized to maintain an opening tothe medial cavity to allow the implant to be inserted therethrough. Withthe prosthetic device secured within the knee joint, the shape of theimplant and the compression forces applied across the implant duringloading of the knee prevent the implant from slipping out of place.

Referring again to FIG. 25, the method 320 continues at step 336 withchecking the knee motion with the prosthetic device implanted. In someembodiments, step 336 is substantially similar to step 332 where thetrial implants are evaluated. Accordingly, in some embodiments step 336comprises confirming the actual implant performs as suggested by themonitoring of the trial implant at step 332. If, for some reason, theknee functionality with the prosthetic device implanted is impaired, theprosthetic device may be adjusted, replaced with an alternativeprosthetic device, or otherwise modified to correct the problem. Afterthe knee motion has been checked and confirmed to be acceptable, themethod 320 concludes at step 338 with the suturing and bandaging of theknee.

Though not described in the above methods, in some instances, thefemoral condyle and/or other aspects of the knee joint are surgicallyprepared to permit near-normal knee joint flexion after implantation.Further, the tibial plateau and/or other aspects of the knee joint aresurgically prepared to fixedly engage the implanted prosthetic device insome instances. Other modifications of the above methods will beapparent to those skilled in the art without departing from the scope ofthe present disclosure.

Referring now to FIGS. 28-34, shown therein are embodiments ofprosthetic devices for monitoring a load or pressure on the knee joint.In some instances, the prosthetic devices of FIGS. 28-34 are trialprosthetic devices utilized to evaluate a perspective prosthetic devicefor a particular patient. In that regard, in some instances a trialprosthetic device is positioned within a knee joint of the patient andsubjected to a load. The resultant peak and/or average pressures acrossthe trial prosthetic device and/or the pressure distribution across thetrial prosthetic device are compared to medically accepted values inorder to evaluate the suitability of the trial prosthetic device for thepatient's knee.

Referring more particularly to FIG. 28, shown therein is a prostheticdevice 400 according to one embodiment of the present disclosure. Inthat regard, the prosthetic device 400 is a meniscus replacement devicethat comprises an upper surface 402 for engaging a portion of a femur,an opposing lower surface (not shown) for engaging a portion of a tibia,and an outer rim 404 extending between the upper and lower surfaces. Theprosthetic device 400 also includes a load sensor or pressure sensor406. In some instances, the pressure sensor 406 is a single sensor. Inother instances, the pressure sensor 406 is a plurality of sensorsspaced throughout the device 400. Generally, the pressure sensor(s) 406are configured to measure the pressures across the prosthetic device400, from which peak and/or average pressures can be calculated and/orthe pressure distribution across the trial prosthetic device can bemapped. In some instances, the pressure sensor(s) 406 are pressuresensors available from Tekscan, Inc. located at 307 West First Street,South Boston, Mass. 02127-1309, USA. In that regard, in some instancesthe sensor(s) 406 are imbedded into the prosthetic device 400. In someembodiments, the sensor(s) 406 substantially comprise the upper and/orlower surface of the prosthetic device 400. In some embodiments, thesensor(s) are positioned within the body of the prosthetic device 400and spaced from the upper and lower surfaces.

The thickness of the sensor(s) 406 is taken into consideration informing the prosthetic device 400 in some instances. In that regard, insome instances the prosthetic device 400 is a trial prosthetic devicerepresentative of a permanent or long-term prosthetic device that may ormay not include sensors. Accordingly, in some instances the prostheticdevice 400 is sized to substantially match the geometries of thelong-term prosthetic device. Thus, in some instances the thickness ofthe sensor(s) 406 is accounted for in forming the prosthetic device 400to substantially match the long-term prosthetic device. In that regard,in some embodiments the sensor(s) 406 comprise a sensor film or sheethaving a thickness less than about 0.5 mm and, in some instances, lessthan about 0.1 mm. In some instances, the sensor(s) are sufficientlythin that they do not materially affect the geometries of the implant.Accordingly, in some instances the prosthetic device 400 is formed byadding the sensor(s) 406 to the corresponding long-term prostheticdevice. For example, in some instances the sensor(s) 406 are secured toat least one of the outer surfaces of the long-term prosthetic. In otherinstances, the prosthetic device 400 is formed in substantially the samemariner as the long-term prosthetic device, but incorporates thesensor(s) 406.

As shown in FIG. 28, the prosthetic device 400 also includes acommunication link 408. Generally, the communication link 408 is anysuitable for transmitting data collected by the sensor(s) 406 to anexternal device, such as a computer or other processing system. In thatregard, the communication link 408 is in communication with thesensor(s) 406 and/or a storage device or memory associated with thesensor(s) in order to communicate the pressure data obtained by thesensor(s) to an external device for processing and analysis. In someinstances, the communication link 408 facilitates a wired connection tothe external device. In some instances, the wired connection comprises aUSB connection, a firewire connection, a serial connection, a digitalconnection, an analog connection, and/or other suitable wiredconnection. In some instances, the communication link 408 facilitates awireless connection to the external device. In some instances, thewireless connection comprises a bluetooth connection, an 802.11connection, and/or other suitable wireless connection.

In some instances, the prosthetic device 400 is used as a trialprosthetic device to measure pressures associated with loading of a kneejoint with the prosthetic device 400 positioned therein. In this manner,the prosthetic device 400 is utilized to evaluate a correspondinglong-term prosthetic device in some instances. In some instances, aplurality of long-term prosthetic devices are available from a libraryof prosthetic devices for consideration for use in a patient's knee. Insome such instances, two or more of the trial versions of the availableprosthetic devices including sensors are trialed and subjected to anequivalent and/or known load while positioned within the knee joint. Theresultant pressure measurements for each of the prosthetic devices arecompared to medically accepted values and/or the values associated witha natural, healthy meniscus in order to evaluate the prosthetic deviceswith respect to pressure distribution, peak pressure, and/or averagepressure data. For example, in some instances the tibialis plateaupressure distributions for each prosthetic device are compared to thoseof a healthy natural meniscus in terms of contact area size and/orstress concentrations. The prosthetic devices are evaluated or scoredbased on how well its pressure distribution matches the accepted valuesassociated with a healthy natural meniscus. In one particularembodiment, a prosthetic device is considered acceptable for use if theresultant pressure distribution across the tibialis plateau is within±15% of a healthy natural meniscus. Further, in some instances the peakpressure measurements of each of the prosthetic devices are compared tothe accepted ranges or the peak pressure measurements of the natural,healthy meniscus. The extent to which the prosthetic device is withinthe accepted range determines the particular device's grade orevaluation for peak pressure. Similarly, in some instances, the peak andaverage pressure acting on the articular cartilages are compared to theallowed natural values for each prosthetic device and the prostheticdevice is evaluated accordingly. In some instances, the accepted valuesfor a healthy natural meniscus are based on one or more large scalestudies as discussed above.

Referring now to FIG. 29, shown therein is a prosthetic device 410according to another embodiment of the present disclosure. In someaspects the prosthetic device 410 is similar to the prosthetic device400 describe above. In that regard, the prosthetic device 410 is ameniscus replacement device that comprises an upper surface for engaginga portion of a femur, an opposing lower surface for engaging a portionof a tibia, and an outer rim extending between the upper and lowersurfaces. The prosthetic device 400 also includes load sensors orpressure sensors 412, 414, 416, 418, 420, 422, 424, 426, and 428. Insome instances, the pressure sensors 412, 414, 416, 418, 420, 422, 424,426, and 428 are regions of a single sensor. In other instances, thepressure sensors 412, 414, 416, 418, 420, 422, 424, 426, and 428 areeach a separate sensor. Generally, the pressure sensors 412, 414, 416,418, 420, 422, 424, 426, and 428 are configured to measure the pressuresacross the prosthetic device 410, from which peak and/or averagepressures can be calculated and/or the pressure distribution across thetrial prosthetic device can be mapped. In some instances, theorientation of the sensors 412, 414, 416, 418, 420, 422, 424, 426, and428 is such that the sensors are associated with a particular region ofthe prosthetic device 410. As discussed in greater detail below, in someinstances the prosthetic device 410 is evaluated regionally and/orglobally based on the obtained pressure measurements. Thus, in suchinstances data of a single sensor (or area of a sensor) is associatedwith a corresponding region of the prosthetic device 410. In someinstances the sensors 412, 414, 416, 418, 420, 422, 424, 426, and 428are imbedded into the prosthetic device 410. In some embodiments, thesensors 412, 414, 416, 418, 420, 422, 424, 426, and 428 substantiallycomprise the upper and/or lower surface of the prosthetic device 410. Insome embodiments, the sensors 412, 414, 416, 418, 420, 422, 424, 426,and 428 are positioned within the body of the prosthetic device 410 andspaced from the upper and lower surfaces.

Referring now to FIG. 30, shown therein is a prosthetic device 430according to another embodiment of the present disclosure. In someaspects the prosthetic device 430 is similar to the prosthetic devices400 and 410 describe above. In that regard, the prosthetic device 430 isa meniscus replacement device that comprises an upper surface forengaging a portion of a femur, an opposing lower surface for engaging aportion of a tibia, and an outer rim extending between the upper andlower surfaces. The prosthetic device 430 also includes load sensors orpressure sensors 432, 434, 436, 438, 440, 442, 444, 446, and 448. Insome instances, the pressure sensors 432, 434, 436, 438, 440, 442, 444,446, and 448 are regions of a single sensor. In other instances, thepressure sensors 432, 434, 436, 438, 440, 442, 444, 446, and 448 areeach a separate sensor. In some instances, separate pressure sensors432, 434, 436, 438, 440, 442, 444, 446, and 448 are in communicationwith one another or a central device to establish a sensor array.Generally, the pressure sensors 432, 434, 436, 438, 440, 442, 444, 446,and 448 are configured to measure the pressures across the prostheticdevice 430, from which peak and/or average pressures can be calculatedand/or the pressure distribution across the trial prosthetic device canbe mapped. In some instances, the orientation of the sensors 432, 434,436, 438, 440, 442, 444, 446, and 448 is such that the sensors areassociated with a particular region of the prosthetic device 430. Asdiscussed in greater detail below, in some instances the prostheticdevice 430 is evaluated regionally and/or globally based on the obtainedpressure measurements. Thus, in such instances data of a single sensoris associated with a corresponding region of the prosthetic device 430.In some instances the sensors 432, 434, 436, 438, 440, 442, 444, 446,and 448 are imbedded into the prosthetic device 430. In someembodiments, the sensors 432, 434, 436, 438, 440, 442, 444, 446, and 448substantially comprise the upper and/or lower surface of the prostheticdevice 430. In some embodiments, the sensors 432, 434, 436, 438, 440,442, 444, 446, and 448 are positioned within the body of the prostheticdevice 430 and spaced from the upper and lower surfaces.

Referring now to FIG. 31, shown therein is a prosthetic device 450according to one embodiment of the present disclosure. In some aspectsthe prosthetic device 450 is similar to the prosthetic devices 400, 410,and 430 describe above. In that regard, the prosthetic device 450 is ameniscus replacement device that comprises an upper surface 452 forengaging a portion of a femur, an opposing lower surface 454 forengaging a portion of a tibia, and an outer rim 456 extending betweenthe upper and lower surfaces 452 and 454. The prosthetic device 450 alsoincludes a load or pressure sensor 458. In the illustrated embodiment,the sensor 458 substantially comprises the upper surface 452.Accordingly, the sensor 458 will engage the patient's femur whenpositioned within the knee joint Thus, in some instances the sensor 458measures pressures or loads imparted upon the prosthetic device 450 bythe femur during loading of the knee joint. These measured pressures orloads are compared to desired or accepted pressure or load values, insome instances, in order to evaluate the effectiveness of the prostheticdevice 450.

Referring now to FIG. 32, shown therein is a prosthetic device 460according to one embodiment of the present disclosure. In some aspectsthe prosthetic device 460 is similar to the prosthetic devices 400, 410,430, and 450 describe above. In that regard, the prosthetic device 460is a meniscus replacement device that comprises an upper surface 462 forengaging a portion of a femur, an opposing lower surface 464 forengaging a portion of a tibia, and an outer rim 466 extending betweenthe upper and lower surfaces 462 and 464. The prosthetic device 460 alsoincludes a load or pressure sensor 468. In the illustrated embodiment,the sensor 468 is positioned within the body of the prosthetic device460 and is spaced, at least slightly, from the upper and lower surfaces462, 464 of the prosthetic device. Accordingly, the sensor 468 does notdirectly engage the patient's femur or tibia when positioned within theknee joint. However, the sensor 468 measures pressures or loads impartedupon the prosthetic device 450 by the femur and/or tibia during loadingof the knee joint. These measured pressures or loads are compared todesired or accepted pressure or load values, in some instances, in orderto evaluate the effectiveness of the prosthetic device 460.

Referring now to FIG. 33, shown therein is a prosthetic device 470according to one embodiment of the present disclosure. In some aspectsthe prosthetic device 470 is similar to the prosthetic devices 400, 410,430, 450, and 460 describe above. In that regard, the prosthetic device470 is a meniscus replacement device that comprises an upper surface 472for engaging a portion of a femur, an opposing lower surface 474 forengaging a portion of a tibia, and an outer rim 476 extending betweenthe upper and lower surfaces 472 and 474. The prosthetic device 470 alsoincludes an upper load or pressure sensor 478 and a lower load orpressure sensor 479. In the illustrated embodiment, the sensor 478substantially comprises the upper surface 472. Accordingly, the sensor478 will engage the patient's femur when positioned within the kneejoint. Thus, in some instances the sensor 478 measures pressures orloads imparted upon the prosthetic device 470 by the femur duringloading of the knee joint. Further, in the illustrated embodiment thesensor 479 substantially comprises the lower surface 474. Accordingly,the sensor 479 will engage the patient's tibia when positioned withinthe knee joint. Thus, in some instances the sensor 479 measurespressures or loads imparted upon the prosthetic device 470 by the tibiaduring loading of the knee joint. The pressures or loads measured by thesensors 478, 479 are compared to desired or accepted pressure or loadvalues, in some instances, in order to evaluate the effectiveness of theprosthetic device 470.

Referring now to FIG. 34, shown therein is a schematic diagram of aprosthetic device 480 according to one embodiment of the presentdisclosure. In some instances, the prosthetic device 480 is particularlysuited as a long-term prosthetic device and/or a longer-term trialprosthetic device. In that regard, in some instances the prostheticdevice 480 is configured to monitor pressures or loads imparted upon theprosthetic device 480 over a time period more than 24 hours, more than 1week, more than 1 month, and/or more than 1 year. In some instances, theprosthetic device 480 is implanted into the patient's knee on a trialbasis. Subsequently, the pressure or load data obtained by theprosthetic device is analyzed in order to evaluate the effectiveness ofthe prosthetic device 480. If the prosthetic device 480 is suitable forthe patient, then either the prosthetic device 480 is maintained withinthe patient's knee for long-term use or the prosthetic device 480 isremoved and replaced with a corresponding long-term prosthetic device.If the prosthetic device 480 is not suitable for the patient, then theprosthetic device 480 is removed from the patient's knee and analternative prosthetic device is implanted. The replacement oralternative prosthetic device is a trial prosthetic device in someinstances. In other instances, the replacement or alternative prostheticdevice is a long-term prosthetic device.

Accordingly, the prosthetic device 480 includes one or more load orpressure sensors 482. Generally, the sensor(s) 482 are configured tomeasure the pressures or loads across the prosthetic device 480 duringloading of the knee joint. The sensor(s) 482 are in communication with asignal processor 484. The signal processor 484 processes the dataobtained from the sensor(s) 482. In some instances, the signal processor484 directs the raw data obtained from the sensor(s) 482 to memory 486or other storage media where the raw data is saved. In other instances,the processor 484 processes the raw data from the sensor(s) in order tocalculate peak and/or average pressures and/or the pressure distributionacross the prosthetic device 480. In some instances, these calculationsare performed on a regional and/or sensor-by-sensor basis. Accordingly,in some instances data representative of these calculated measurementsare stored in the memory 486 along with or in lieu of the raw data fromthe sensor(s). The prosthetic device 480 also includes communicationcircuitry 488. The communication circuitry 488 facilitates communicationof the data stored in the memory 486 to an external device. Accordingly,the communication circuitry 488 is any suitable device for communicatingwith an external device, including wired and wireless communicationprotocols. Finally, the prosthetic device 480 includes a power supply489 for providing power to the other components of the prosthetic deviceas needed. In some instances, the power supply is a battery. In someinstances, the power supply is rechargeable.

Referring now to FIG. 35, shown therein is a system 490 according to oneaspect of the present disclosure. In that regard, a prosthetic device492 is positioned between a femur 494 and a tibia 496 of a knee joint.The fibula 498 and patella 500 are also shown. The prosthetic device 492is a prosthetic device in accordance with the present disclosure havingone or more load or pressure sensors for monitoring a load or pressureimparted upon the prosthetic device 492. The prosthetic device 492 is incommunication with an external device 502. In the illustratedembodiment, the prosthetic device 492 communicates with the externaldevice 502 via line 504. In some instances, the line 504 is a USB cable,firewire cable, or other suitable communication cable. In someinstances, the external device 502 is a computer or other processingsystem for processing data received from the prosthetic device 492. Insome instances, the external device 502 receives data from theprosthetic device 492 as the prosthetic device 492 is subjected toloads. In other instances, the external device 502 receives data storedby the prosthetic device 492 indicative of previous loadings of theprosthetic device. In that regard, the external device 502 is configuredto process and analyze the pressure and load data measured by thesensors of the prosthetic device 492 to evaluate the effectiveness ofthe prosthetic device in some instances.

Referring now to FIG. 36, shown therein is a system 510 according toanother aspect of the present disclosure. In some aspects, the system510 is similar to the system 490 shown above. However, the system 510illustrates wireless communication between the prosthetic device andexternal device. In that regard, a prosthetic device 512 is positionedbetween a femur 494 and a tibia 496 of a knee joint. The fibula 498 andpatella 500 are also shown. The prosthetic device 512 is a prostheticdevice in accordance with the present disclosure having one or more loador pressure sensors for monitoring a load or pressure imparted upon theprosthetic device 512. The prosthetic device 512 is in communicationwith an external device 514. In the illustrated embodiment, theprosthetic device 512 communicates with the external device 514wirelessly, as indicated by signal 516. In some instances, the wirelesssignal 516 is communicated using bluetooth, 802.11, or other suitablewireless communication protocols. In some instances, the external device514 is a computer or other processing system for processing datareceived from the prosthetic device 512. In some instances, the externaldevice 514 is a handheld device. In some instances, the external device514 receives data from the prosthetic device 512 as the prostheticdevice 512 is subjected to loads. In other instances, the externaldevice 514 receives data stored by the prosthetic device 512 indicativeof previous loadings of the prosthetic device. In that regard, theexternal device 514 is configured to process and analyze the pressureand load data measured by the sensors of the prosthetic device 512 toevaluate the effectiveness of the prosthetic device in some instances.

In some instances, the prosthetic device is positioned within subjectknee and the patient is positioned on a machine for applying a fixed orknown amount of mechanical compression or loading upon the knee joint.With the patient positioned on the machine, the knee is positioned atzero degrees of flexion and all degrees of freedom of the knee are fixedto prevent unwanted bending of the knee during the compression test. Themachine then applies mechanical compression or loading to the kneejoint. In some instances, the amount of mechanical compression orloading is increased (either incrementally or continuously) until adesired maximum compression or loading force is reached. In someinstances, the maximum load is between about 800N and about 2000N. Insome instances, the maximum load is approximately 1200N. In someinstances, the maximum load applied is at least partially based on thepatient's weight and/or activity level. In some instances, the machineapplies mechanical compression or loading to the knee joint in cycles,such that the amount of compression or loading is varied. In some suchinstances, the loading cycles are representative of the loading of theknee joint associated with walking, running, or other common loadingcycles. In some instances, the load varies between about 0N and about2000N during the loading cycles. In some embodiments, the amount of loadapplied to the knee is controlled through a software interface. In someinstances, a user controls the amount of load applied to the knee viathe user interface. In some instances, the user controls the cycle ofloading applied to the knee via the user interface.

Corresponding pressure maps are obtained from the pressure sensorswithin the prosthetic device based on the loading of the knee joint. Thepressure maps are displayed via a software interface in someembodiments. In some instances, the same software interface (orcoordinated software interfaces) is utilized for both controlling theamount of load applied to the knee and displaying the correspondingpressure maps. The pressure maps are stored in an accessible database insome instances. In that regard, the pressure maps are associated withcharacteristics of the knee being tested (such as tibial, femoral, andmeniscal dimensions and/or other characteristics) and/or patientcharacteristics (such as weight, activity level, and/or othercharacteristics) such that the pressure maps and associated data areretrievable for use in future prosthetic device selection methods.

In some instances the pressure distribution maps attained from theprosthetic devices are analyzed and compared to the pressuredistribution maps attained from one or more cadaveric knees. Thepressure distribution maps are analyzed and compared on a regionalbasis, a global basis, or a combination thereof. In some instances, acomparison of local or regional characteristics is advantageous inidentifying small, but possibly critical variations in the pressure mapsand/or in emphasizing regions of interest. Furthermore, measurement ofthe total contact area on a global basis and/or global contact pressuresmay not reveal potentially problematic discrepancies in the contactareas and pressure points of the prosthetic devices. Quantization of thesmaller regional areas better approximates the specific shape of thecontact areas and the maximum pressure points in some instances. Basedon the shape of the natural meniscus, the pressure maps are divided into9 regions in some embodiments. For example, FIG. 22 illustrates oneembodiment of a pressure map shown divided into the 9 separaterectangular regions. Similarly, FIGS. 29 and 30 illustrate prostheticdevices 410 and 430 adapted for monitoring pressures in the 9 regions asshown in the pressure map of FIG. 22. In other instances, the pressuremaps are divided into other numbers of regions and/or regions havingshapes other than rectangular. Accordingly, the prosthetic devicesinclude similar distributions of sensors and/or sensor regions in thesealternative regional breakdowns. In some instances, the regionalboundaries of the sensor(s) are determined by a software interface thatprocesses the data received from the prosthetic device.

In some instances, the pressure distributions or pressure maps of thetrial prosthetic devices are compared to the accepted pressuredistributions for a healthy meniscus. In some instances, the prostheticdevices are scored based on how well the device's pressure map comparesto the accepted pressure distributions. In one embodiment, one or moreof 3 different measurements are utilized to evaluate the pressure mapsof the prosthetic devices: global contact area, regional contact area,and peak regional pressures. These measurements are utilizedindividually and/or in combination to evaluate the effectiveness and/orsuitability of a particular prosthetic device for a particular patient.

The first measurement is the global contact area or utilization of areadetermination, where the total contact area of the prosthetic deviceunder load is compared to the established value for total contact areaof a healthy meniscus. In some instances, this determination is based onwhether the total contact area is within a certain percentage of theaccepted value. In that regard, in some instances the acceptablepercentage variation is between about ±30%. In some instances, theacceptable percentage variation is between about ±20%. In otherinstances, the acceptable percentage variation is between about ±10%. Insome instances, the acceptable percentage variation is selected by thetreating medical personnel. If the prosthetic device is within theacceptable percentage variation for utilization of area, then it isconsidered a suitable prosthetic device in some instances. In otherinstances, if the prosthetic device is within the acceptable percentagevariation for utilization of area, then additional factors areconsidered to determine whether the prosthetic device is a suitableprosthetic device. If the prosthetic device is not within the acceptablepercentage variation for utilization of area, then it is not considereda suitable prosthetic device in some instances. In other instances, ifthe prosthetic device is not within the acceptable percentage variationfor utilization of area, then additional factors are considered todetermine whether the prosthetic device is a suitable prosthetic device.Where additional factors are considered, the utilization of area isweighted in the overall evaluation of the prosthetic device. Forexample, in some instances the utilization of area is weighted to bebetween 0% and 50% of the overall evaluation of the prosthetic devices.

Generally, the regional contact area parameter is determined, evaluated,and weighted in a manner similar to that of the global contact areadiscussed above. For example, in some instances a contact area for eachregion is compared to the established value for the contact area of thatregion of a healthy meniscus. In some instances, this determination isbased on whether the total contact area is within a certain percentageof the accepted value. In that regard, in some instances the acceptablepercentage variation is between about ±30%. In some instances, theacceptable percentage variation is between about ±20%. In otherinstances, the acceptable percentage variation is between about ±10%. Insome instances, the acceptable percentage variation is selected by thetreating medical personnel. If the prosthetic device is within theacceptable percentage variation for all of the regions, then it isconsidered a suitable prosthetic device in some instances. In someinstances, if the prosthetic device is within the acceptable percentagevariation for a majority of the regions, then it is considered asuitable prosthetic device. In other instances, the regions are weightedand a score for each region is obtained. One specific weightingdistribution, based on a 9 region analysis as shown in FIG. 22, is setforth in Table 5 above. The sum of the scores for each region providesan overall regional contact score for the device. If the total scoremeets a predetermined threshold, then the prosthetic device isconsidered a suitable prosthetic device in some instances. In otherinstances, additional factors are considered to determine whether theprosthetic device is a suitable prosthetic device regardless of whetherall or some of the regions are within the acceptable percentagevariation and regardless of the overall regional contact score. Whereadditional factors are considered, the regional contact area is weightedin the overall evaluation of the prosthetic device. For example, in someinstances the regional contact area is weighted to be between 0% and 50%of the overall evaluation of the prosthetic devices.

Finally, peak contact pressures for each of the regions are alsoconsidered in some embodiments. In some instances, the peak contactpressure for each region is compared to the accepted peak contactpressure for a healthy meniscus. In other instances, the ratio of thepeak contact pressure to the average contact pressure for each region iscompared to the accepted ratio of peak contact pressure to averagecontact pressure. In some instances, this determination is based onwhether the peak contact pressure or ratio of peak contact pressure toaverage contact pressure is within a certain percentage of the acceptedvalue. In that regard, in some instances the acceptable percentagevariation is between ±30%. In some instances, the acceptable percentagevariation is between about ±20%. In other instances, the acceptablepercentage variation is between about ±10%. In some instances, theacceptable percentage variation is selected by the treating medicalpersonnel. If the prosthetic device is within the acceptable percentagevariation for all of the regions, then it is considered a suitableprosthetic device in some instances. In some instances, if theprosthetic device is within the acceptable percentage variation for amajority of the regions, then it is considered a suitable prostheticdevice. In other instances, the regions are weighted and a score foreach region is obtained. One specific weighting distribution, based on a9 region analysis as shown in FIG. 22, is set forth in Table 6 above.The sum of the scores for each region provides an overall regional peakcontact pressure score for the device. If the total score meets apredetermined threshold, then the prosthetic device is considered asuitable prosthetic device in some instances. In other instances,additional factors are considered to determine whether the prostheticdevice is a suitable prosthetic device regardless of whether all or someof the regions are within the acceptable percentage variation andregardless of the overall regional peak contact pressure score. Whereadditional factors are considered, the regional peak contact pressure isweighted in the overall evaluation of the prosthetic device. Forexample, in some instances the regional peak contact pressure isweighted to be between 0% and 50% of the overall evaluation of theprosthetic devices.

In some instances, the overall evaluation of the prosthetic device isdetermined by considering the evaluations for the utilization of area,regional contact area, and regional peak contact pressure together. Insome instances, one or more additional parameters are taken intoconsideration in evaluating the prosthetic devices. For example, in someinstances implant movement or dislocation is considered. In that regard,if unwanted movement or dislocation of the prosthetic device occursduring trialing of the prosthetic device, then the prosthetic device isnot a suitable prosthetic device for the patient. However, if nounwanted movement or dislocation occurs, then the prosthetic device isconsidered suitable. In some instances, implant impingement uponsurrounding ligaments or anatomy is considered. In that regard, if theprosthetic device impinges on any cruciate ligaments or othersurrounding anatomy that will be detrimental to the performance of theprosthetic device, then the prosthetic device is not consideredsuitable. However, if no such impingement occurs, then the prostheticdevice is considered suitable. In some instances, the score of theprosthetic device takes into account both the implant movement ordislocation and implant impingement.

Referring now to FIGS. 37-44, shown therein are various screen shotsrepresentative of a user interface associated with a system forimplementing the methods and prosthetic devices of the presentdisclosure according to one embodiment of the present disclosure.Additional and/or alternative features of the user interface will beapparent from the following description. Further, some aspects of themethod(s) associated with the user interface that are not described ingreat detail are found above with respect to other embodiments of thepresent disclosure. In some aspects the user interface and theunderlying methods comprise a semi-automated procedure or wizard forselecting a prosthetic device suitable for a particular patient.

Referring more specifically to FIG. 37, shown therein is a screen shot600 showing a patient list in a file tree structure of the userinterface according to one aspect of the present disclosure. In thatregard, the system stores details and information related to eachpatient. Personal data is uploaded to the system and stored according toFDA standards regarding patients' confidentiality. The system maintainsa database containing all of the patient data. In some instances, thedatabase stores patient data for more than one user (e.g., treatingphysician). In such instances, the system restricts access to thepatient data to which the particular user is entitled to view.

Referring to FIG. 38, shown therein is a screen shot 610 showing apatient detail page for one of the patients of the patient list of FIG.37. Personal data includes such information as gender, age, weight,height (or BMI), medical history (including previous MRI prognoses),and/or other pertinent medical or personal information. The user has theability to add an up-to-date prognosis of the current medical status andspecific pre-operation information to the patient's detail page. Theuser also has the ability to add any other detail or notes regarding thepatient that the user considers relevant.

Referring to FIG. 39, shown therein is a screen shot 620 showing an MRIimage of the patient's knee within the user interface in accordance withone aspect of the present disclosure. In that regard, in some instancesMRI images of the patient's knee(s) are uploaded to the system and/ormoved within a file folder associated with the patient in someinstances. In some instances, the user accesses the drive or memorydevice in which MRI data is located. Upon accessing the MRI data, thesystem identifies the existing MRI-sequences and presents them as a filetree on the left side of the screen. In that regard, the systemidentifies and indicates the scan type (T1, T2 etc), slice thickness,overlapping/gap, and distance between slices in some instances. The userhas the ability to browse between the different images of the differentseries and add comments to the patient's personal data, if warranted. Insome instances, from the different images the user identifies or selectsfor the system the relevant series for the sizing process: coronal,sagittal, and axial scans. In some instances, the preferred scan is T1.In some instances, T2 or PD scans are utilized. The user also excludesnon-relevant images from each of the selected MRI-series by marking orselecting the non-relevant images from the series of images in someinstances. For example, if the first image of the axial series is asagittal image for some reason, then the first image will not be takeninto account after the user excludes the first image.

In some instances, from the coronal images the user indicates for thesystem the lateral side of the knee by clicking on the fibula bone whenprompted by the system. In that regard, clicking on the fibula involvesaligning a cursor associated with a mouse or other input device of thesystem with the lateral side of the fibula and activating a button orother mechanism of the mouse or other input device to communicate to thesystem the position of the lateral side of the fibula as viewed in therelevant image. The user also identifies the posterior image for thesizing process (Cor-P-End) as the last image that the tibia can berecognized. Further, the user identifies the anterior image for thesizing process (Cor-A-End) as the last image that the tibia can berecognized.

Similarly, in some instances from the sagittal images the user indicatesfor the system the lateral side of the knee by clicking on the fibulabone when asked. The user also identifies the medial image of the medialtibialis plateau for the sizing process (Sag-M-End), as the last imagethat the tibia can be recognized. The user also identifies the lateralimage of the medial tibialis plateau for the sizing process (Sag-L-End)as the first image in which the femur notch can be recognized.

Further, in some instances from the axial images the user indicates forthe system the lateral side of the knee by clicking on the fibula bonewhen asked. The user also identifies the femur image for the sizingprocess (Ax-F), as the first image in which both femoral condyles can beconsidered as connected. The user also identifies the tibia image forthe sizing process (Ax-T), as the first image in which the tibialisplateau articular cartilage cannot be recognized (e.g., only bone isvisible in the image).

From the user inputs, the system determines the relevant MRI images forthe sizing process. In some instances, the relevant MRI images aredetermined in the following manner. For the coronal plane images thesystem counts the number of images between Cor-P-End and Cor-A-End. Themiddle image is identified as Cor-Mid. If the number of images betweenCor-P-End and Cor-A-End is even, then the image of the two middle imagesin which the tibialis plateau is wider, as measured by side-to-sidedistance, is identified as Cor-Mid. Next, the system counts the numberof images between Cor-Mid and Cor-A-End. The middle image will beidentified as Cor-A. If the number of images between Cor-Mid andCor-A-End is even, then the image of the two middle images that isclosest to Cor-Mid is identified as Cor-A. Finally, the system countsthe number of images between Cor-Mid and Cor-P-End. The middle imagewill be identified as Cor-P. If the number of images between Cor-Mid andCor-P-End is even, then the image of the two middle images that isclosest to Cor-Mid is identified as Cor-P.

For the sagittal plane images, the system counts the number of imagesbetween Sag-M-End and Sag-L-End. The middle image is identified asSag-Mid. If the number of images between Sag-M-End and Sag-L-End iseven, then the image of the two middle images that is closest toSag-L-End is identified as Sag-Mid. Next, the system counts the numberof images between Sag-Mid and Sag-M-End. The middle image is identifiedas Sag-M. If the number of images between Sag-Mid and Sag-M-End is even,then the image of the two middle images that is closest to Sag-Mid isidentified as Sag-M. Finally, the system counts the number of imagesbetween Sag-Mid and Sag-L-End. The middle image is identified as Sag-L.If the number of images between Sag-Mid and Sag-L-End is even, then theimage of the two middle images that is closest to Sag-Mid is identifiedas Sag-L.

Referring now to FIG. 40, shown therein is a screen shot 630 showing astartup screen of an implant size selection wizard in accordance withone aspect of the present disclosure. In that regard, afterdetermination of the relevant images for sizing process a wizard or userguide will prompt the user step-by-step through the subsequent sizingand measurement process. For example, regarding the coronalmeasurements, the Cor-Mid image is uploaded and shown on the screen ordisplay visible to the user. In some instances, the system guides theuser through determining the femoral and tibial functional directions.In one example, on the Cor-Mid image, the user marks the two lowestpoints, one on each condyle lower border that are used as tangentialend-points of a single line. A perpendicular line to the aforementionedline is considered as the femur functional direction at the coronalplane (FFD). The same direction (FFD) is used for the femur in allcoronal measurements. Similarly, the user marks the two highest points,one on each side of the tibialis plateau upper border (medial andlateral) that are used as tangential end-points of a single line. Aperpendicular line to the aforementioned line is considered as the tibiafunctional direction at the coronal plane (TFD). The same direction(TFD) is used for the tibia in all coronal measurements.

From the Cor-Mid image several measurements are obtained by the system.First, several femur measurements are obtained. For example, in oneembodiment three lines, parallel to FFD are located on the Cor-Mid imageby the system. The user locates or positions two of the lines on themost medial and lateral edges of the condyles and the Femur CondyleWidth (FCW) is determined therefrom. The third line is located orpositioned by the user on the medial condyle lower border, where the“bending” to the notch is initiating. The Medial Femur Width (FW) isdetermined by the distance between this line and the aforementionedmedial line. Further, several tibia measurements are obtained for theCor-Mid image. For example, in one embodiment three lines, parallel toTFD are automatically located on the Cor-Mid image. The user locates orpositions two lines on the most medial and lateral edges of the tibialisplateau and the Tibialis Plateau Width (TPW) is determined therefrom.For example, referring to FIG. 41, shown therein is a screen shot 640showing the wizard prompting the user to position the lines forobtaining the Tibialis Plateau Width (TPW) in accordance with one aspectof the present disclosure. The third line is located or positioned bythe user on the medial apex of the intercondylar eminence. The TibialisPlateau Medial Width (MW) is determined by the distance between thisline and the aforementioned medial line.

From the Cor-A image several measurements are also obtained by thesystem. First, several femur measurements are obtained. For example, inone embodiment three lines, parallel to FFD are located on the Cor-Aimage by the system. The user locates or positions two of the lines onthe most medial and lateral edges of the condyles and the AnteriorMedial Femur Condyle Width (FCWA) is determined therefrom. The thirdline is located or positioned by the user between the condyles on thehighest point of the notch. The Anterior Medial Femur Width (FWA) isdetermined by the distance between this line and the aforementionedmedial line. Further, several tibia measurements are obtained from theCor-A image. For example, in one embodiment three lines, parallel to TFDare automatically located on the Cor-A image. The user locates orpositions two lines on the most medial and lateral edges of the tibialisplateau and the Tibialis Plateau Anterior Width (TPWA) is determinedtherefrom. The third line is located or positioned by the user on themedial apex of the intercondylar eminence. The Tibialis Plateau AnteriorMedial Width (MWA) is determined by the distance between this line andthe aforementioned medial line.

From the Cor-P image several measurements are also obtained by thesystem. First, several femur measurements are obtained. For example, inone embodiment three lines, parallel to FFD are located on the Cor-Pimage by the system. The user locates or positions two of the lines onthe most medial and lateral edges of the condyles and the PosteriorMedial Femur Condyle Width (FCWP) is determined therefrom. The thirdline is located or positioned by the user between the condyles on thehighest point of the notch. The Posterior Medial Femur Width (FWP) isdetermined by the distance between this line and the aforementionedmedial line. Further, several tibia measurements are obtained from theCor-P image. For example, in one embodiment three lines, parallel to TFDare automatically located on the Cor-P image. The user locates orpositions two lines on the most medial and lateral edges of the tibialisplateau and the Tibialis Plateau Posterior Width (TPWP) is determinedtherefrom. The third line is located or positioned by the user on themedial apex of the intercondylar eminence. The Tibialis PlateauPosterior Medial Width (MWP) is determined by the distance between thisline and the aforementioned medial line.

Regarding the sagittal measurements, the Sag-Mid image is uploaded andshown on the screen or display visible to the user. In some instances,the system guides the user through determining the femoral and tibialfunctional directions. In the sagittal plane, the femur and tibia sharethe same defined direction. In one example, on the Sag-Mid image, theuser marks the two highest points, one on each side of the tibialisplateau upper border (anterior and posterior) that are used astangential end-points of a single line. A perpendicular line to theaforementioned line is considered as the knee functional direction atthe sagittal plane (SFD). The same functional direction (SFD) is usedfor both the femur and the tibia in all sagittal measurements.

From the Sag-Mid image several measurements are obtained by the system.First, at least one femur measurement is obtained. For example, in oneembodiment two lines, parallel to SFD are located on the Sag-Mid imageby the system. The user locates or positions the two lines on the medialand lateral edges of the condyles and the Medial Femoral Condyle Length(FL) is determined by the distance therebetween. For example, referringto FIG. 42, shown therein is a screen shot 650 showing the wizardprompting the user to position the lines for obtaining the MedialFemoral Condyle Length (FL) in accordance with one aspect of the presentdisclosure. Similarly, at least one tibia measurement is obtained. Inthat regard, two lines, parallel to SFD are located on the Sag-Mid imageby the system. The user locates or positions the two lines on the medialand lateral edges of the tibia and the Tibialis Plateau Medial Length(ML) is determined by the distance therebetween.

From the Sag-M image several measurements are also obtained by thesystem. For example, in one embodiment two lines, parallel to SFD arelocated on the Sag-M image by the system. The user locates or positionsthe two lines on the medial and lateral edges of the condyles and theMedial Femoral Condyle Length-Medial Edge (FLM) is determined by thedistance therebetween. Similarly, at least one tibia measurement isobtained. In that regard, two lines, parallel to SFD are located on theSag-M image by the system. The user locates or positions the two lineson the medial and lateral edges of the tibia and the Tibialis PlateauMedial Length-Medial Edge (MLM) is determined by the distancetherebetween.

Further, from the Sag-L image several measurements are obtained by thesystem. For example, in one embodiment two lines, parallel to SFD arelocated on the Sag-L image by the system. The user locates or positionsthe two lines on the medial and lateral edges of the condyles and theMedial Femoral Condyle Length-Lateral Edge (FLL) is determined by thedistance therebetween. Similarly, at least one tibia measurement isobtained. In that regard, two lines, parallel to SFD are located on theSag-L image by the system. The user locates or positions the two lineson the medial and lateral edges of the tibia and the Tibialis PlateauMedial Length-Lateral Edge (MLL) is determined by the distancetherebetween.

Regarding the axial measurements, the Ax-F image is uploaded and shownon the screen or display visible to the user. On the Ax-F image, theuser marks the area defined by the femoral condyles using a spline toolbased on “point-after-point” procedure to form a closed loop. The systemcalculates the area defined by the point-after-point procedure todetermine the Femoral Condyles Area (FA). For example, referring to FIG.43, shown therein is a screen shot 660 showing the wizard prompting theuser to point-trace the femoral condyles border in order to obtain theFemoral Condyle Area (FA) in accordance with one aspect of the presentdisclosure. The user also indicates the lowest and highest points of theconnection between the condyles to form a mid-line dividing betweenmedial and lateral sides. Based on the mid-line, the system calculatesthe Femoral Condyle Medial Area (FMA).

Similarly, the Ax-T image is uploaded and shown on the screen or displayvisible to the user. On the Ax-T image, the user marks the area definedby the tibialis plateau using a spline tool based on “point-after-point”procedure to form a closed loop. The system calculates the area definedby the point-after-point procedure to determine the Tibialis PlateauArea (TA). Further, based on a mid-line, the system calculates theTibialis Plateau Medial Area (TMA). In some instances, a mid-linecorresponding to the mid-line defined for the Ax-F image is utilized. Inother instances, the user indicates upper and lower midpoints of thetibialis plateau from which a mid-line is defined and utilized forcalculating the Tibialis Plateau Medial Area (TMA).

After obtaining the desired measurements, the measurements are utilizedto select a suitable prosthetic device from a library of availableprosthetic devices. For exemplary purposes, a library containing 13prosthetic devices of similar structure but varying size is discussed.In that regard, the prosthetic devices are indicated by two digitreference numerals from 00 to 120 in multiples of 10 (i.e., 00, 10, 20,. . . , 110, 120). However, no limitations are intended thereby. Rather,the library includes additional or fewer prosthetic devices in someinstances. Further, in some instances the library includes prostheticdevices having different structures and/or features in addition todifferent sizes. The corresponding measurement for each prostheticdevice size (00 to 120) is compared to the measurements obtained fromthe MRI analysis. A particular prosthetic device size receives a singlepoint if the size of the prosthetic device falls within the normativerange for that measurement as determined by the MRI analysis, where thenormative range is defined by the actual measurement value determined bythe MRI analysis plus the standard deviation for that measurement as setforth in Table 2 above. It should be noted that more than one prostheticdevice size will get a point from the same measurement in someinstances. Adding up the scores for each measurement, each size ofprosthetic device will have a final score. In some instances, theanalysis includes 22 measurements, so the maximum score for any oneprosthetic device is 22 points. In other instances, additional or fewermeasurements are utilized. Further, in some instances the measurementsare weighted to highlight the importance of certain measurements.

The prosthetic device size with the highest score will be identified bythe system as the optimal prosthetic device for the patient. Forexample, as shown in the chart 670 of FIG. 44, the prosthetic devicesize 90 having a score of 18 is identified as the optimal prostheticdevice for the patient. In the case where two prosthetic device sizeshave the same total score, then the size closer to where the scoringtrend is located will be selected. For example, as shown in the chart672 of FIG. 45, the prosthetic device sizes 80 and 90 have the sametotal score of 17, but the larger size prosthetic devices (i.e., 100 and110) have substantially greater scores than the smaller size prostheticdevices (i.e., 60 and 70). Accordingly, in this instance the trending istowards the larger prosthetic devices. Accordingly, the prostheticdevice 90 is selected as the optimal prosthetic device for the patient.If there is no discernable difference in the trending where twoprosthetic devices have the same total score, then the smaller of thetwo sizes is selected. In the case of three prosthetic device sizeshaving equal scores, the middle size is selected and identified as theoptimal prosthetic device for the patient. For example, as shown in thechart 674 of FIG. 46, the prosthetic device sizes 80, 90, and 100 allhave the same total score of 14. Accordingly, the prosthetic device size90 is identified as the optimal prosthetic device for the patient.Referring to FIG. 47, shown therein is a screen shot 680 showing thewizard indicating to the user that prosthetic device size 60L is theoptimal prosthetic device for the patient in accordance with one aspectof the present disclosure.

While the principles of the present disclosure have been set forth usingthe specific embodiments discussed above, no limitations should beimplied thereby. Any and all alterations or modifications to thedescribed devices, instruments, and/or methods, as well as any furtherapplication of the principles of the present disclosure that would beapparent to one skilled in the art are encompassed by the presentdisclosure even if not explicitly discussed herein. It is alsorecognized that various presently unforeseen or unanticipatedalternatives, modifications, and variations of the present disclosuremay be subsequently made by those skilled in the art. All suchvariations, modifications, and improvements that would be apparent toone skilled in the art to which the present disclosure relates areencompassed by the following claims.

1. A method of selecting a meniscus prosthetic device for a patient froma library of available meniscus prosthetic devices, the methodcomprising: utilizing a pre-implantation matching process to identifytwo or more most suitable meniscus prosthetic devices from the libraryof available prosthetic devices for replacing the damaged meniscus ofthe patient; obtaining two or more trial prosthetic devicescorresponding to the two or more most suitable prosthetic devicesidentified by the pre-implantation matching process; positioning a firsttrial prosthetic device of the two or more trial prosthetic deviceswithin a knee joint of the patient; loading the knee joint of thepatient with the first trial prosthetic device positioned within theknee joint; and measuring a contact pressure distribution between thefirst trial prosthetic device and a tibialis plateau of the knee jointduring loading of the knee joint with the first trial prosthetic devicepositioned within the knee joint.
 2. The method of claim 1, furthercomprising comparing the measured contact pressure distribution to adesired contact pressure distribution.
 3. The method of claim 2, whereincomparing the measured contact pressure distribution to the desiredcontact pressure distribution comprises comparing a pressure map basedon the measured contact pressure distribution to a desired pressure mapbased on the desired contact pressure distribution.
 4. The method ofclaim 3, wherein the pressure maps are compared on a region-by-regionbasis.
 5. The method of claim 2, further comprising evaluating the firsttrial prosthetic device based on the comparison of the measured contactpressure distribution to the desired contact pressure distribution. 6.The method of claim 1, further comprising: positioning a second trialprosthetic device of the two or more trial prosthetic devices within aknee joint of the patient; loading the knee joint of the patient withthe second trial prosthetic device positioned within the knee joint; andmeasuring a contact pressure distribution between the second trialprosthetic device and a tibialis plateau of the knee joint duringloading of the knee joint with the second trial prosthetic devicepositioned within the knee joint.
 7. The method of claim 6, furthercomprising comparing the measured contact pressure distributions of thefirst and second trial prosthetic devices to a desired contact pressuredistribution.
 8. The method of claim 7, wherein comparing the measuredcontact pressure distributions to the desired contact pressuredistribution comprises comparing pressure maps based on the measuredcontact pressure distributions to a desired pressure map based on thedesired contact pressure distribution.
 9. The method of claim 7,evaluating the first and second trial prosthetic devices based on thecomparison of the measured contact pressure distributions to the desiredcontact pressure distribution to identify which of the first and secondtrial prosthetic devices is best suited for the patient.
 10. The method,of claim 1, wherein measuring the contact pressure distribution betweenthe first trial prosthetic device and a tibialis plateau comprisesobtaining data from at least one pressure sensor associated with thefirst trial prosthetic device.
 11. The method of claim 10, wherein theat least one pressure sensor is positioned within the first trialprosthetic device.
 12. The method of claim 10, wherein loading the kneejoint of the patient comprises imparting a load of between about 800 Nand about 1600 N with the knee joint at a flexion angle of approximately0°.
 13. The method of claim 12, wherein the load is imparted on the kneeby a machine.
 14. The method of claim 12, wherein the load is impartedon the knee manually by medical personnel.
 15. A method for selecting ameniscus prosthetic device for a patient from a library of availablemeniscus prosthetic devices, the method comprising: obtaining aplurality of trial prosthetic devices, each trial prosthetic devicehaving a profile corresponding to one of the available meniscusprosthetic devices of the library, and each trial prosthetic devicecomprising one or more pressure sensors for measuring a load imparted onthe trial prosthetic device; positioning a first trial prosthetic deviceselected from the plurality of trial prosthetic devices within a kneejoint of the patient; loading the knee joint of the patient with thefirst trial prosthetic device positioned within the knee joint;obtaining a pressure distribution across the first trial prostheticdevice based on measurements from the one or more pressure sensorsduring loading of the knee joint with the first trial prosthetic devicepositioned within the knee joint; and evaluating the first trialprosthetic device based on the pressure distribution.
 16. The method ofclaim 15, further comprising: positioning a second trial prostheticdevice selected from the plurality of trial prosthetic devices within aknee joint of the patient; loading the knee joint of the patient withthe second trial prosthetic device positioned within the knee joint;obtaining a pressure distribution across the second trial prostheticdevice based on measurements from the one or more pressure sensorsduring loading of the knee joint with the second trial prosthetic devicepositioned within the knee joint; and evaluating the second trialprosthetic device based on the pressure distribution.
 17. The method ofclaim 16, further comprising comparing the evaluations of at least thefirst and second trial prosthetic devices to identify a most suitableprosthetic device for the patient.
 18. The method of claim 15, whereinevaluating the first trial prosthetic device comprises comparing themeasured pressure distribution to a desired pressure distribution. 19.The method of claim 18, wherein the comparing of the measured pressuredistribution to the desired pressure distribution is performed on aregional basis.
 20. The method of claim 19, wherein each of the regionsis weighted based on importance.